Testing And Adjusting

Usage:

Basic Engine Troubleshooting

Introduction

NOTE: For Specifications with illustrations, make reference to Specifications For 3176B Marine Engine, SENR6507. If the Specifications in SENR6507 are not the same as in the Systems Operation, Testing and Adjusting, look at the printing date on the back cover of each book. Use the Specifications given in the book with the latest date.

Troubleshooting can be difficult. The Troubleshooting Index gives a list of possible problems. To make a repair to a problem, see the possible cause and corrective action on the pages that follow. Also, check the 3176B Electronic Troubleshooting, SENR6500.

This list of problems, causes and corrections will only give an indication of where a possible problem can be, and what repairs are needed.

Service personnel may remember similar complaints which were corrected by a previous method of troubleshooting. However, just because the complaint is the same the cause for the complaint can be different.

Be sure to get a good description of the problem from the operator and/or the person who owns the vehicle. What they tell you about the problem can save you time and make the repair job faster and easier.

1. Loud Combustion Noise

2. Fuel Consumption Too High

3. Too Much Black Or Gray Smoke

4. Too Much White Smoke

5. Too Much Blue Smoke

6. Engine Has Low Oil Pressure

7. Engine Overheating

8. Engine Excessive Cooling

9. Coolant Leaks Outside Of Engine

10. Coolant Leaks At The Overflow Tube

11. Coolant Leakage Inside Engine

Troubleshooting Problems

Problem 1: Loud Combustion Noise

Probable Cause:

1. Poor Quality Or Water In Fuel

Follow the recommendations given in Special Instruction, SEHS7067, Fuel Recommendations For Caterpillar Diesel Engines. Also, Special Instruction, SEHS6947 has fuel correction factors and tables.

2. Wrong Timing Position Sensor Calibration

Refer to 3176B Electronic Troubleshooting, SENR6500.

Problem 2: Fuel Consumption Too High

Probable Cause:

1. Fuel Consumption Errors

Follow high fuel consumption check list:

* Fuel measured correctly

* Comparison to other marine applications

* Different marine craft or engine specifications

* Different operating loads

* Different operating modes

2. Poor Quality Or Water In Fuel

Follow the recommendations given in Special Instruction, SEHS7067, Fuel Recommendations For Caterpillar Diesel Engines. Also, Special Instruction, SEHS6947 has fuel correction factors and tables.

3. Fuel System Leaks

Inspect the fuel system for leaks and make repairs or replacements as needed.

4. Excess Idle Time

Shut engine off when not in use.

5. Fuel And Combustion Noise (knock)

Refer to 3176B Electronic Troubleshooting, SENR6500.

6. Wrong Timing Position Sensor Calibration

Refer to 3176B Electronic Troubleshooting, SENR6500.

Problem 3: Too Much Black Or Gray Smoke

Probable Cause:

1. Not Enough Air For Combustion

Check for a plugged air cleaner element or blockage in the air lines. Follow the procedures in the Testing and Adjusting section to check inlet manifold pressure and aftercooler core leakage.

2. Wrong Timing Position Sensor Calibration

Refer to 3176B Electronic Troubleshooting, SENR6500.

Problem 4: Too Much White Smoke

Probable Cause:

1. Too Much Oil In Engine

Do not put too much oil in the crankcase. If the oil level in the crankcase goes up as the engine is used, check for fuel in the crankcase. Make repairs or replacements to the fuel injection lines and nozzles as needed to keep fuel out of the crankcase.

2. Engine Misfires Or Runs Rough

Check items listed in Problem No. 3. Refer to 3176B Electronic Troubleshooting, SENR6500.

3. Wrong Timing Position Sensor Calibration

Refer to 3176B Electronic Troubleshooting, SENR6500.

4. Coolant In Combustion System

Coolant in the combustion chamber can cause white smoke. A cracked cylinder head or liner, also a bad cylinder head gasket are possible causes for this condition.

Problem 5: Too Much Blue Smoke

1. Failed Turbocharger Oil Seal

Check inlet manifold and aftercooler core for oil. Make a repair or replacement of the turbocharger as needed.

2. Worn Valve Guides

See the Specifications module for the maximum permissible wear of the valve guides.

3. Worn Piston Rings

Worn piston rings and/or cylinder walls can be the cause of blue smoke and can cause a loss of compression. Make a visual inspection of the cylinder walls and piston rings. If necessary, measure the cylinder walls and piston rings. For the cylinder and piston ring specifications, see the Specifications module. NOTE: High wear at low mileage is normally caused by dirt coming into the engine with the inlet air.

Problem 6: Engine Has Low Oil Pressure

Probable Cause:

1. Low Engine Oil Level

Check engine oil level and fill to proper level.

2. Oil Leaks

Check for loose oil filter or oil supply lines, etc.

3. Dirty Oil Filter Or Cooler Core

Check the operation of bypass valve for the filter. Install new oil filter elements if needed. Clean or install new oil cooler core. Remove dirty oil and fill the engine with clean oil to the correct level.

4. Diesel Fuel In Lubricating Oil

Find the place where diesel fuel gets into the lubrication oil. Make repairs as needed. Remove any oil that has diesel fuel in it. Install new oil filters and fill the engine with clean oil to the correct level.

5. Too Much Clearance Between Rocker Arm Shaft And Rocker Arms

Check for correct lubrication in valve compartment. Install new parts as necessary.

6. Oil Pump Suction Pipe Has A Defect.

Replacement of the pipe is needed.

7. Relief Valve For Oil Pump Does Not Operate Correctly

Clean valve and housing. Install new parts as necessary.

8. Oil Pump Has A Defect

Make a repair or replacement of the oil pump as needed.

9. Too Much Clearance Between Camshaft And Camshaft Bearings

Install new camshaft and camshaft bearings if necessary.

10. Too Much Clearance Between Crankshaft And Crankshaft Bearings

Inspect the bearings and crankshaft journals and make repairs and replacements as necessary.

11. Too Much Bearing Clearance For Idler Gear

Inspect bearings and make replacements as necessary.

12. Piston Oil Cooling Jet Tubes Not Installed

Install piston oil cooling jet tubes.

13. Defective Oil Pressure Gauge

Replace oil pressure gauge

Problem 7: Engine Overheating

Probable Cause:

1. Low Coolant Level

If the coolant level is too low, not enough coolant will go through the engine and heat exchanger. This lack of coolant will not take enough heat from the engine and there will not be enough flow of coolant through the heat exchanger to release the heat into the water cooled exhaust manifold. Low coolant level is caused by leaks or wrong filling of the cooling system. With the engine cool, be sure the coolant can be seen in the heat exchanger tank.

2. Defective Temperature Gauge

A temperature gauge which does not work correctly will not show the correct temperature. If the temperature gauge shows that the coolant temperature is too hot but other conditions are normal, either install a gauge you know is good or check the cooling system with the 4C6500 Digital Thermometer Group.

3. Defective Hose(s)

Defective hoses with leaks can normally be seen. Hoses that have no visual leaks can "collapse" (pull together) during operation and cause a restriction in the flow of coolant. Hoses become soft and/or get cracks after a period of time. See Operation & Maintenance Manual for the frequency to change hoses. The inside of the hose can become loose, and the loose particles of can cause a restriction in the flow of coolant.

4. Defective Water Temperature Regulator (thermostat)

A regulator that does not open, or only opens part of the way, can cause above normal heating. See the Testing and Adjusting section for the procedure to test water temperature regulators.

5. Defective Water Pump

A water pump with a loose impeller does not pump enough coolant for correct engine cooling. A loose impeller can be found by removing the water pump, and by pushing the shaft back and pulling it forward. If the impeller has no damage, check the impeller clearance.

6. Air In Cooling System

Air can get into the cooling system in different ways. The most common causes are not filling the cooling system correctly, and combustion gas leaking into the system. Combustion gas can get into the system through inside cracks or bad cylinder head gaskets. Air in the cooling system causes a reduction in coolant flow and bubbles in the coolant. Air bubbles hold coolant away from engine parts, preventing heat flow.

7. Engine Used In A Lug Condition

"Lugging" (when the vessel is used in a range too high for engine rpm to go up as the engine is accelerated or engine rpm goes down with engine at full throttle) the engine causes the engine rpm to be low. This low rpm causes a reduction in the flow of coolant through the system. This less coolant flow during high input of fuel will cause above normal heating.

8. Air Inlet Restriction

Restriction of the air coming into the engine causes high cylinder temperatures and more than normal amount of heat to pass to the cooling system. Check for a restriction with a water manometer or a vacuum gauge (which measures in inches of water). Connect the gauge to the engine air inlet between the air cleaner and the inlet to the turbocharger. With gauge installed, run engine at full load rpm and check the restriction. Maximum restriction of air inlet 635 mm (25 inches) of water. If the indication is higher than the maximum permissible restriction, remove the dirt from the filter element, or install a new filter element and check the restriction again. If the indication is still too high, there must be a restriction in the inlet piping.

9. Exhaust Restriction

Restriction in the exhaust system causes high cylinder temperatures and more than normal amount of heat to pass to the cooling system. To see if there is an exhaust restriction, make a visual inspection of the exhaust system. If no damage is found, check the system for back pressure from the exhaust (pressure difference measurement between exhaust outlet and atmosphere). The back pressure must not be more than 1016 mm (40 inches) of water. You can also check the system by removing the exhaust pipes from the exhaust manifolds. With the exhaust pipes removed, start and run the engine to see if the problem is corrected.

10. Fuel Injection Timing Not Correct

Check and make necessary adjustments as given in the Testing and Adjusting section.

Problem 8: Engine Excessive Cooling

Probable Cause:

1. Long Idle Periods

When the engine is running with no load, only a small quantity of fuel is burnt and engine heat is removed too fast.

2. Very Light Load

Very light loads, and a very slow speed can cause excessive cooling because of the low heat input of the engine.

3. Defective Water Temperature Regulator (thermostat)

A regulator that is "stuck" open (will not move to the closed position) will cause overcooling. A thermostat that is stuck between the open and closed positions, or only opens part of the way, can cause overcooling. Also, coolant leaks around the thermostat, such as vent lines, can cause overcooling.

Problem 9: Coolant Leaks Outside Of Engine

Probable Cause:

1. Leaks In Hoses Or Connections

Check all hoses and connections for visual signs of leakage. If no leaks are seen, look for damage to hoses or loose clamps.

2. Leaks In Heat Exchanger

Put pressure to the heat exchanger tank with the 9S8140 Cooling System Pressurizing Pump Group and check for leaks. Refer to Testing Heat Exchanger Cooling System For Leaks in Testing And Adjusting Section.

3. Leaks In The Water Pump

Check the water pump for leaks before starting the engine, then start the engine and look for leaks. If there are leaks at the water pump, repair or install a new water pump.

4. Cylinder Head Gasket Leakage

Look for leaks along the surface of the cylinder head gasket. If you see leaks, install a new head gasket.

Problem 10: Coolant Leaks At The Overflow Tube

Probable Cause:

1. Defective Pressure Cap Or Relief Valve

Check the sealing surfaces of the pressure cap and the radiator to be sure the cap is sealing correctly. Check the opening pressure and sealing ability of the pressure cap or relief valve with the 9S8140 Cooling System Pressurizing Pump Group. Refer to Checking Pressure Cap in Testing And Adjusting Section.

2. Engine Runs Too Hot

If coolant temperature is too high, pressure will be high enough to move the cap off of the sealing surface in the radiator and cause coolant loss through the overflow tube. See Problem 7: Engine Overheating.

3. Cylinder Head Gasket Leakage Or Crack(s) In Cylinder Head Or Cylinder Block

Remove the radiator cap and, with the engine running, look for air bubbles in the coolant. Bubbles in the coolant are a sign of probable leakage at the head gasket. Remove the cylinder head from the engine. Check cylinder head, cylinder walls and head gasket surface of the cylinder block for cracks. When the head is installed, use a new head gasket, spacer plate gasket, water seals, and O-ring seals.

Problem 11: Coolant Leakage Inside Engine

Probable Cause:

1. Cylinder Head Gasket Leakage

If the cylinder head gasket leaks between a water passage and an opening into the crankcase, coolant will get into the crankcase.

2. Crack(s) In Cylinder Head

Crack(s) in the upper surface of the cylinder head, or an area between a water passage and an opening into the crankcase, can allow coolant to get into the crankcase.

3. Crack(s) In Cylinder Block

Crack(s) in the cylinder block between a water passage and the crankcase will let coolant get into the crankcase.

Diagnostic Codes

For an explanation of each diagnostic code see 3176B Marine Engine, Electronic Troubleshooting, SENR6500.

Active Diagnostic Codes

Diagnostic codes are used by the 3176B System to warn the vehicle operator of a problem and indicate to the service technician the nature of the problem. Some codes are used only to record an event and do not indicate problems that need repair.

An ACTIVE diagnostic code represents a problem that should be investigated and corrected AS SOON AS POSSIBLE. Repairing the cause of an ACTIVE code will cause the code to be cleared.

When an ACTIVE code is generated, the diagnostic lamp will turn ON and remain ON, blinking every five seconds. If the condition generating the fault occurs only for a brief moment, the lamp will go OFF after five seconds and the code will be LOGGED.

There are a few codes which are not a response to a performance problem, but merely record an event such as 35 and 55. In these cases troubleshooting is not required.

Some Diagnostic Codes cause the 3176B System to make major changes in engine operation or limits, as a result of the code being generated.

Logged Diagnostic Codes And Events

When the ECM generates a diagnostic code, it usually logs the code in permanent memory within the ECM. The ECM has an internal diagnostic clock and will record the hour EACH time a code is logged. Knowing when and how often the code was generated can be a valuable indicator when troubleshooting intermittent problems. Logged codes can be retrieved or erased using an ECAP Electronic Service Tool. They can be a valuable indicator when troubleshooting intermittent problems.

* Diagnostic Codes that are logged repeatedly may indicate a problem that needs special investigation. Codes that are logged only a few times and do not result in driver complaints, may not need attention until a scheduled maintenance interval.

To troubleshoot a Logged Diagnostic Code, refer to the "Troubleshooting Diagnostic Codes" section in Electronic Troubleshooting, 3176B Marine Engine, SENR6500. If symptoms continue, refer to "Troubleshooting Without A Diagnostic Code" section in Electronic Troubleshooting, SENR6500.

* The most likely cause of an intermittent problem is a faulty connection or damaged wiring. Next likely is a component failure (sensor or switch for example). Least likely is the ECM itself.

3176B Electronic Service Tools

The Caterpillar Service Tools for the 3176B Electronic Control System are designed to help the service technician analyze and locate faults or problems within the system. Their use is required to perform sensor calibrations and to read or change programmable engine parameters.

The tools have small plug-in modules, called Service Program Modules (SPM), to adapt the basic tools to a particular engine or application.

The 3176B Marine Engine requires an Electronic Control Analyzer and Programmer (ECAP) to communicate with the 3176B Electronic Control Module and read Diagnostic Codes. This service tool is able to read the various sensor output signals, as well as switch status (On/Off) inputs. It is capable of electronically calibrating the Boost Sensor, and the ECAP can calibrate the Speed/Timing Sensor. The ECAP can measure Pulse Width Modulated (PWM) signals, such as those produced by the throttle position sensor (PWM Adapter required).

Installation/Removal Of The Speed/Timing Sensors

Engine-Front Right Side
(1) Speed/timing sensor. (2) Speed/timing sensor. (3) Front gear cover.

1. Disconnect speed/timing connectors P8/J8 and P9/J9 and inspect for corrosion, bent or missing pins and sockets, and mismating, broken wires, etc.

2. Remove the speed/timing sensors (1) and (2) from front gear cover (3).

3. Examine the plastic end of the sensor for signs of wear or contaminants such as metal filings. The plastic end of the speed/timing sensor should have no contaminants or show no wear [greater than 0.051 mm (.0020 in) from its face].

4. Use a screwdriver to carefully pry the plastic sensor end to the fully Extended position [approximately 4.775 mm (.1880 in) beyond the metal housing of the sensor].

5. Gently push in on the plastic end of the sensor. The plastic end should be firm and resist movement in the retract direction. If there is no resistance replace the sensor.

Locating Top Center
(4) Bolts (two-6V5219). (5) Cover. (6) Flywheel housing.

6. Remove two bolts (4) and remove cover (5) from the flywheel housing (6) to open the hole for engine turning.

7. Put one of the 6V5219 bolts (4) in the timing hole located approximately 127 to 152 mm (5 to 6 in) above the hole in the flywheel housing for engine turning. Use the 9S9082 Engine Turning Tool and a 1/2 inch drive ratchet wrench to turn the engine flywheel in the direction of normal engine rotation (counterclockwise when viewed from the flywheel end) until the timing bolt engages with the threaded hole in the flywheel.

NOTE: The No. 1 piston must be at either top center of the compression stroke or top center of the exhaust stroke.

8. To install the speed/timing sensor, first perform the sensor inspections described in steps 3 through 6.

9. If the sensor end is not fully extended, use a screwdriver to carefully pry the plastic sensor end to the fully EXTENDED position [approximately 4.775 mm (.1880 in) beyond the metal housing of the sensor].

10. Examine the O-ring seal at the base of the sensor threads. If it is missing or damaged, install a new O-ring seal.

11. Install the speed/timing sensors into the front gear cover. Tighten to a torque of 23.5 ± 3.5 N·m (17.5 ± 2.5 lb ft).

12. Connect the P8/J8 and P9/J9 connector for the speed/timing sensors.

NOTE: Be sure that the P8/J8 and P9/J9 connectors are properly fastened.

NOTE: The electronic injection timing must be recalibrated after reinstallation of the speed/timing sensor (see Electronic Troubleshooting SENR6500. See topic, Calibrating Electronic Injection Timing With The Timing Adapter Tool Group And The ECAP).

Throttle Position Sensor Adjustment

The throttle position sensor (TPS) is used to provide a throttle signal to the Electronic Control Module (ECM). Sensor output is a constant frequency signal whose pulse width varies with throttle position. This output signal is referred to as either "Duty Cycle" or a "Pulse Width Modulated (PWM)" signal and is expressed as a percentage. When correctly adjusted, the TPS will produce a "Duty Cycle" signal of 10 to 22 percent at the low idle throttle position and 75 to 90 percent at the maximum throttle position. This signal is translated by the ECM into a "Throttle Position" signal of three percent at low idle and 100 percent at maximum throttle.

Throttle Sensor

Calibration of the Throttle Sensor is done automatically by the ECM. The correct calibration can be displayed with the ECAP. The correct percent throttle (governor control movement) is displayed as three percent with the throttle completely released, and 100 percent with the throttle completely depressed.

Fuel System

Fuel System Components
(1) Fuel temperature sensor. (2) Adaptor (siphon break and regulator). (3) Fuel line (ECM to fuel filter base). (4) Fuel supply and return manifold. (5) Fuel line (fuel transfer pump to ECM). (6) Fuel outlet (from fuel transfer pump). (7) Fuel transfer pump. (8) Fuel inlet (to fuel transfer pump). (9) ECM. (10) Fuel line (filter base to supply manifold).

Fuel System Components
(3) Fuel line (ECM to fuel filter base). (10) Fuel line (filter base to supply manifold). (11) Fuel priming pump. (12) Fuel temperature sensor. (13) Fuel filter.

Either too much fuel or not enough fuel for combustion can be the cause of a problem in the fuel system. Many times work is done on the fuel system when the problem is really with some other part of the engine. The source of the problem is difficult to find, especially when smoke comes from the exhaust. Smoke that comes from the exhaust can be caused by a defective unit injector, but it can also be caused by one or more of the reasons that follow:

a. Not enough air for good combustion.

b. An overload at high altitude.

c. Oil leakage into combustion chamber.

d. Not enough compression.

e. Fuel injection timing incorrect.

Fuel System Inspection

A problem with the components that send fuel to the engine can cause low fuel pressure. This can decrease engine performance.

1. Check the fuel level in the fuel tank. Look at the cap for the fuel tank to make sure the vent is not filled with dirt.

2. Check fuel lines for leakage. Be sure none of the fuel lines have a restriction or a defective bend. Verify that the fuel return line has not collapsed in the sections subject to heat.

3. Install a new fuel filter.

4. Remove any air that may be in the fuel system. Refer to Fuel Priming Procedure in this service manual.

Fuel Transfer Pump

With the engine operating at rated rpm and load condition, the fuel transfer pump moves fuel through the ECM, fuel filter base, and fuel supply and return manifolds. An orificed valve in the return fuel manifold regulates fuel flow. The normal fuel pressure is 630 kPa (91 psi) at rated rpm.

If the fuel pressure is low 517 kPa (75 psi) or less, stop the engine. Replace the fuel filter, and make sure the fuel lines are not plugged or damaged.

Start the engine and again check the fuel pressure. If the fuel pressure is not above the low specification, a replacement of the fuel transfer pump is needed.

If the fuel pressure is high 690 kPa (100 psi) or above, stop the engine. Remove the fuel regulating valve from the adaptor (siphon break and regulator). The valve is directly behind the return line fitting. Check for debris plugging the orifice holes near the tip. If plugged, flush any remaining debris from the return passage, and check source of debris. If not plugged, check for plugged return fuel line. If no obstructions were found, check the fuel transfer pump relief valve.

Fuel Pressure

To check the fuel transfer pump pressure, remove the fuel pressure sensor from the fuel filter base. Install a pressure gauge, and start the engine.

The 1U5470 Engine Pressure Group can be used to check engine fuel pressure.

This tool group has a gauge to read fuel pressure to the fuel supply manifold. Special Instruction, SEHS8907 is with the tool group and gives information for its use.

1U5470 Engine Pressure Group

Fuel Priming Procedure

Siphon Break Adaptor
(1) Adaptor. (2) Air bleed port plug. (3) Fuel inlet line.

NOTE: Each time the fuel system is run out of fuel or air is introduced into the system the following procedure must be followed.

1. After fuel is added to the fuel tank, remove plug (2) in fuel adapter at the Air Bleed port.

2. Use the hand priming pump to pump fuel into the system. Stop pumping when fuel appears at the port.

3. Plug the bleed port. Continue pumping until a strong pressure is felt on the pump, and you hear a "click" from the fuel adaptor. This will require about 75 strokes. When finished, LOCK THE PUMP in the bottom position to avoid possible damage to the pump.

4. Crank the engine as soon as you can after pressurizing the system. It should start within 15 seconds. If not started after 30 seconds, stop and wait two minutes. Repeat Step 3 to repressurize the system, and crank engine again for up to 30 seconds.

Unit Injector Adjustment

Injector Mechanism
(1) Rocker arm. (2) Adjusting screw. (3) Locknut.

To make an adjustment to the unit injector, turn the adjusting screw in the rocker arm. Unit injector adjustment can be make by using the procedure that follows:

1. Put No. 1 piston at top center (TC) on the compression stroke. See the topic, Finding Top Center Position For No. 1 Piston.

2. Turn the unit injector adjusting screw (2) CW (clockwise) until contact is made with the unit injector.

3. Turn the adjusting screw CW (clockwise) an additional 180 degrees (1/2 turn).

4. Hold the adjusting screw in this position and tighten the locknut (3) to a torque of 55 ± 10 N·m (41 ± 7 lb ft).

5. Make an adjustment to the unit injectors on cylinders 3, 5, and 6.

6. Remove the timing bolt and turn the flywheel 360 degrees in the direction of engine rotation (counterclockwise). This will put No. 1 piston at top center (TC) on the exhaust stroke.

7. Make an adjustment to the unit injectors on cylinders 1, 2, and 4.

8. Remove the timing bolt from the flywheel when all the unit injector adjustments have been made, and reinstall the timing cover.

Checking Engine Cylinders Separately

Temperature of an exhaust manifold port, when the engine runs at low idle speed, can be an indication of the condition of a fuel injector. Low temperature at an exhaust manifold port is an indication of no fuel to the cylinder. This could be caused by an inoperative injector pump. Extra high temperature at an exhaust manifold port can be an indication of too much fuel to the cylinder, caused by a malfunctioning injector pump.

Use the 1U8865 Infrared Thermometer to check exhaust temperature. The Operator's Manual, NEHS0510, for the 1U8865 Infrared Thermometer gives complete operating and maintenance instructions for this tool.

Static Check Of The Timing Gear Position Used To Reference Electronic Injection Timing / Front Gear Group Alignment

Front Gear Group (with front cover removed)
(1) Camshaft gear / timing reference ring. (2) Timing marks. (3) Idler gear. (4) Crankshaft gear.

The basis for correct fuel injection timing and valve mechanism operation is determined by the timing reference ring and the alignment of the front gear group. The timing reference ring is located on the end of the camshaft group, and it is used to measure crankshaft rotation. During installation of the front gear group, timing marks (2) on idler gear (3) must be in alignment with the timing marks on crankshaft gear (4) and the timing marks on camshaft gear (1). For a complete removal and installation procedure of the front gear group, see the topic, Front Gear Group, in the Disassembly and Assembly module.

NOTE: It is possible to install the Timing Reference Ring backwards. If this occurs, the engine will not start.

Check for proper alignment of the timing reference ring (1) on the camshaft assembly with the alignment marks on idler gear (3) and crankshaft gear (4). Inspect the key between the timing reference ring and the camshaft gear. Check the timing ring teeth. The teeth should not be defaced, and should have sharp clean edges and be free of contaminants.

NOTE: The electronic injection timing must be calibrated after re-assembly of the front gear train.

Finding Top Center Position For No. 1 Piston

Locating Top Center
(1) Bolts (two-6V5219). (2) Cover. (3) Flywheel housing.

1. Remove two bolts (1) and remove cover (2) from the flywheel housing (3) to open the turning hole.

2. Put one of the 6V5219 bolts (1) in the timing hole located approximately 127 to 152 mm (5 to 6 in) above the turning hole in the flywheel housing. Use the 9S9082 Engine Turning Tool and a 1/2 inch drive ratchet wrench to turn the engine flywheel in the direction of normal engine rotation (counterclockwise when viewed from the flywheel end) until the timing bolt engages with the threaded hole in the flywheel.

NOTE: If the flywheel is turned beyond the point that the timing bolt engages in the threaded hole, the flywheel must be turned opposite normal engine rotation approximately 30 degrees. Then turn the flywheel in the direction of normal rotation (counterclockwise) until the timing bolt engages with the threaded hole. The reason for this procedure is to make sure the play is removed from the gears when the No. 1 piston is put on top center.

3. Remove the front valve cover from the engine.

4. The intake and exhaust valves for the No. 1 cylinder are fully closed if No. 1 piston is on the compression stroke and the rocker arms can be moved by hand. If the rocker arms cannot be moved and the valves are slightly open the No. 1 piston is on the exhaust stroke.

NOTE: When the actual stroke position is identified, and the other stroke position is needed, it is necessary to remove the timing bolt from the flywheel, turn the flywheel counterclockwise 360 degrees, and reinstall the timing bolt.

Electronic Injection Timing Troubleshooting

Electronic injection timing troubleshooting is required if the electronic injection timing is inconsistent or it will not calibrate correctly. If either of these conditions are present, see Electronic Troubleshooting, 3176B Engine For Caterpillar Built Engines, SENR6500.

Engine Speed Measurement

6V3121 Multitach Group

The 6V3121 Multitach Group can measure engine speed from a magnetic pickup on the flywheel housing. It also has the ability to measure engine speed from visual engine parts in rotation.

Special Instruction, SEHS7807 is with the 6V3121 Multitach Group and gives instructions for the test procedure.

Air Inlet And Exhaust System

Restriction Of Air Inlet And Exhaust

There will be a reduction of horsepower and efficiency of the engine if there is a restriction in the air inlet or exhaust system.

Air flow through the air cleaner must not have a restriction (negative pressure difference measurement between atmospheric air and air that has gone through air cleaner) of more than 635 mm (25 inches) of water with a used or plugged air cleaner element. Air flow through the air cleaner must not have a restriction (negative pressure difference measurement between atmospheric air and air that has gone through air cleaner) of more than 381 mm (15 inches) of water with a new air cleaner element.

Back pressure from the exhaust (pressure difference measurement between exhaust at outlet elbow and atmospheric air) must not be more than 1016 mm (40 inches) of water.

Measurement of Pressure in Inlet Manifold

The efficiency of an engine can be checked by making a comparison of the pressure in the inlet manifold with the information given in the Fuel Setting And Related Information Fiche. This test is used when there is a decrease of horsepower from the engine, yet there is no real sign of a problem with the engine.

The correct pressure for the inlet manifold is given in the Fuel Setting And Related Information Fiche. Development of this information is done with these conditions:

a. 737 mm (29 in) of mercury (DRY) barometric pressure.

b. 29°C (85°F) outside air temperature.

c. 35 API rated fuel.

On a turbocharged and aftercooled engine, a change in fuel rating will also change horsepower and the pressure in the inlet manifold. If the fuel is rated above 35 API, pressure in the inlet manifold can be less than given in the Fuel Setting And Related Information Fiche.

If the fuel is rated below 35 API, the pressure in the inlet manifold can be more than given in the Fuel Setting And Related Information Fiche. Be Sure That The Air Inlet Or Exhaust Does Not Have A Restriction When Making A Check Of Pressure In The Inlet Manifold.

Pressure Test Location On Inlet Manifold
(1) Plug.

To measure the inlet manifold pressure, remove plug (1) from the inlet manifold. Use the 1U5470 Engine Pressure Group to check the pressure in the inlet manifold.

1U5470 Engine Pressure Group

This tool group has a gauge to read pressure in the inlet manifold. Special Instruction, SEHS8907 is with the tool group and gives instructions for its use.

Exhaust Temperature

Air Aftercooled Systems

Visual Inspection

Inspect all air lines, hoses and gasket connections at each oil change. Make sure the constant torque hose clamps are tightened to the correct torque. Check the truck manufacturer's specifications for the correct torque. Check welded joints for cracks and make sure all brackets are tightened in position and are in good condition. Use compressed air to clean cooler core blockage caused by debris or dust. Inspect the cooler core fins for damage, debris or salt corrosion. Use a stainless steel brush with soap and water to remove corrosion.

Show/hide table

Pressure air can cause personal injury.

When using pressure air for cleaning, wear a protective face shield, protective clothing and protective shoes.

NOTE: When air to air aftercooler system parts are repaired and/or replaced, a leak test is recommended.

Air System Restriction

Pressure measurements should be taken at the turbocharger outlet and at the inlet manifold. When the total pressure drop of the charged air system at maximum air flow exceeds 13.5 kPa (4 inches of Hg), the air lines and cooler core must be inspected for internal restriction and cleaned, repaired or replaced as necessary.

Turbocharger Failure

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Pressure air can cause personal injury.
When using pressure air for cleaning, wear a protective face shield, protective clothing and protective shoes.

The maximum air pressure must be below 205 kPa (30 psi) for cleaning purposes.

If a turbocharger failure occurs, remove the air to air cooler core and flush internally with a solvent that removes oil and other foreign substances. Shake cooler to eliminate any trapped debris. Wash with hot, soapy water; rinse thoroughly with clean water; and blow dry with compressed air in reverse direction of normal air flow. Carefully inspect the system to make sure it is clean.

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NOTICE

Do not use caustic cleaners or damage to the aftercooler core will result.

Inlet Manifold Pressure

Normal inlet manifold pressure with high exhaust temperature can be caused by cooler core fin blockage. Clean the cooler core fins, see Visual Inspection for the cleaning procedure to use.

Low inlet manifold pressure and high exhaust manifold temperature can be caused by any of the conditions that follow:

1. A plugged air cleaner. Clean or replace the air cleaner as needed.

2. A blockage in the air lines between the air cleaner and turbocharger. All restrictions must be removed.

3. Cooler core leakage. Pressure test the cooler core, see Aftercooler Core Leakage for the correct procedure to use and repair or replace parts as needed.

4. Leakage from the pressure side of the induction system. Check and repair leaks.

5. Inlet manifold leak. Check for loose, missing and damaged fittings or plugs. Also check the manifold to cylinder head gaskets.

Crankcase (Crankshaft Compartment) Pressure

Pistons or rings that have damage can be the cause of too much pressure in the crankcase. This condition will cause the engine to run rough. There will also be more than the normal amount of fumes (blowby) coming from the crankcase breather. The breather can then become restricted in a very short time, causing oil leakage at gaskets and seals that would not normally have leakage. Other sources of blowby can be worn valve guides or turbocharger seal leakage.

8T2700 Indicator Group

The 8T2700 Indicator Group is used to check the amount of blowby. The test procedure is in Special Instruction, SEHS8712.

Compression

An engine that runs rough can have a leak at the valves, or have valves that need adjustment. Removal of the head and inspection of the valves and valve seats is necessary to find those small defects that do not normally cause a problem. Repair of these problems is normally done when reconditioning the engine.

Cylinder Head

The cylinder head has valve seat inserts, valve guides and bridge dowels that can be removed when they are worn or have damage. Replacement of these components can be made with the tools that follow. Most of the tools are part of the 1U9654 Head Repair Tool Group.

NOTE: The Disassembly and Assembly module contains a complete procedure for removing and installing the cylinder head components.

Valves

For valve removal and installation use the 5S1330 Valve Spring Compressor Assembly or equivalent, and the 5S1332 Valve Keeper Inserter.

NOTE: A 1U7798 Hammer and 1U7794 Shaft Assembly are used to remove and install the valve seat inserts and valve guides.

Valve Seat Inserts

Tools needed to remove and install the valve seat inserts are: 1U9166 Valve Seat Extractor for intake valves, 1U9167 Valve Seat Extractor for exhaust valves, 1U9170 Valve Seat Driver, and 1U9706 Plate (for exhaust seats).

Valve Guides

Tools needed to remove and install the valve guides are the 1U9168 Valve Guide Collar (Stop) and the 1U9169 Valve Guide Driver.

Checking Valve Guide Bores

Use the 5P3536 Valve Guide Gauge Group to check the bore of the valve guides. Special Instruction, GMG02562 gives complete and detailed instructions for use of the 5P3536 Valve Guide Gauge Group.

Valve Lash Setting

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To prevent possible injury, do not use the starter motor to turn the flywheel.
Hot engine components can cause burns. Allow additional time for the engine to cool before measuring valve lash.

The 3176B uses high voltage to the unit injectors. Do not come in contact with the injector terminals while the engine is running. Disconnect J5/P5.

NOTE: Valve lash is measured between the rocker arm and the bridge for the valves.

NOTE: When the valve lash is checked, adjustment is Not Necessary if the measurement is in the range given in the chart for Valve Lash Check: Engine Stopped. If the measurement is outside this range, adjustment is necessary. See the chart for Valve Lash Setting: Engine Stopped, and make the setting to the nominal (desired) specifications in this chart.

Cylinder And Valve Location

To make an adjustment to the valve lash, turn the adjustment screw in the rocker arm. Valve lash adjustments can be made by using the procedure that follows:

1. Put No. 1 piston at top center (TC) on the compression stroke. See the topic, Finding Top Center Position For No. 1 Piston.

Intake Valve Adjustment
(1) Intake rocker arm. (2) Adjustment locknut.

Exhaust Valve Adjustment
(3) Exhaust rocker arm. (4) Adjustment locknut.

2. Make an adjustment to the valve lash on the intake valves for cylinders 1, 2 and 4. Make an adjustment to the valve lash on the exhaust valves for cylinders 1, 3, and 5.

3. After each adjustment, tighten the nut for valve adjustment screw to a torque of 25 ± 7 N·m (18 ± 5 lb ft), and check the adjustment again.

4. Remove the timing bolt and turn the flywheel 360 degrees in the direction of engine rotation. This will put No. 6 piston at top center (TC) on the compression stroke. Install the timing bolt in the flywheel.

5. Make an adjustment to the valve lash on the intake valves for cylinders 3, 5, and 6. Make an adjustment to the valve lash on the exhaust valves for cylinders 2, 4, and 6.

6. After each adjustment, tighten the nut for valve adjustment screw to a torque of 25 ± 7 N·m (18 ± 5 lb ft), and check the adjustment again.

7. Remove the timing bolt from the flywheel when all adjustments to the valve lash have been made.

Lubrication System

One of the problems in the list that follows will generally be an indication of a problem in the lubrication system for the engine.

* Too Much Oil Consumption

* Oil Pressure Is Low

* Oil Pressure Is High

* Too Much Bearing Wear

* Increased Oil Temperature

Too Much Oil Consumption

Oil Leakage On Outside Of Engine

Check for leakage at the seals at each end of the crankshaft. Look for leakage at the oil pan gasket and all lubrication system connections. Check to see if oil comes out of the crankcase breather. This can be caused by combustion gas leakage around the pistons. A dirty crankcase breather will cause high pressure in the crankcase, and this will cause gasket and seal leakage.

Oil Leakage Into Combustion Area Of Cylinders

Oil leakage into the combustion area of the cylinders can be the cause of blue smoke. There are four possible ways for oil leakage into the combustion area of the cylinders:

1. Oil leakage between worn valve guides and valve stems.

2. Worn or damaged piston rings, or dirty oil return holes.

3. Compression ring and/or intermediate ring not installed correctly.

4. Oil leakage past the seal rings in the impeller end of the turbocharger shaft.

Too much oil consumption can also be the result if oil with the wrong viscosity is used. Oil with a thin viscosity can be caused by fuel leakage into the crankcase or by increased engine temperature.

Measuring Engine Oil Pressure

An oil pressure gauge that has a defect can give an indication of low or high oil pressure

1U5470 Engine Pressure Group

The 1U5470 Engine Pressure Group can be used to measure the pressure in the system. This tool group has a gauge to read pressure in the oil manifold. Special Instruction, SEHS8907 is with the tool group and gives instructions for its use.

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Work carefully around an engine that is running. Engine parts that are hot, or parts that are moving, can cause personal injury.

Engine-Right Side
(1) Plug. (2) Plug.

Oil pressure to the camshaft and main bearings should be checked on the side of the cylinder block at oil gallery plugs (1) or (2). Install the 1U5470 Engine Pressure Group into this opening. With the engine at operating temperature (using SAE 15W40 oil), under full load condition, oil pressure should be 275 to 414 kPa (40 to 60 psi). With the engine at operating temperature (using SAE 15W40 oil), at 600 to 800 rpm low idle, minimum oil pressure is 60 kPa (8.7 psi).

Oil Pressure Is Low

Crankcase Oil Level

Check the level of the oil in the crankcase. Add oil if needed. It is possible for the oil level to be too far below the oil pump supply tube. This will cause the oil pump not to have the ability to supply enough lubrication to the engine components.

Oil Pump Does Not Work Correctly

The inlet screen of the supply tube for the oil pump can have a restriction. This will cause cavitation (low pressure bubbles suddenly made in liquids by mechanical forces) and a loss of oil pressure. Air leakage in the supply side of the oil pump will also cause cavitation and loss of oil pressure. If the bypass valve for the oil pump is held in the open (unseated) position, the lubrication system cannot get to maximum pressure. Oil pump gears that have too much wear will cause a reduction in oil pressure.

Oil Filter Bypass Valve

If the bypass valve for the oil filter is held in the open position (unseated) because the oil filter has a restriction, a reduction in oil pressure can result. To correct this problem, remove and clean the bypass valve and bypass valve bore. Install a new Caterpillar oil filter to be sure that no more debris makes the bypass valve stay open.

Too Much Clearance At Engine Bearings Or Open Lubrication System (Broken Or Disconnected Oil Line Or Passage)

Components that are worn and have too much bearing clearance can cause oil pressure to be low. Low oil pressure can also be caused by an oil line or oil passage that is open, broken or disconnected.

Piston Cooling Jets

When engine is operated, cooling jets direct oil toward the bottom of the piston to cool the piston and also provide lubrication for the piston pin. If a jet is broken, plugged or installed wrong, seizure of the piston will be caused in a very short time.

Oil Pressure Is High

Oil pressure will be high if the bypass valve for the oil pump cannot move from the closed position.

Too Much Bearing Wear

When some components of the engine show bearing wear in a short time, the cause can be a restriction in an oil passage.

If the gauge for oil pressure shows enough oil pressure, but a component is worn because it cannot get enough lubrication, look at the passage for oil supply to the component. A restriction in a supply passage will not let enough lubrication get to a component, and this will cause early wear.

Increased Oil Temperature

With the engine at operating temperature (using SAE 15W40 oil), the maximum oil temperature is 110°C (230°F). This temperature is from or after the oil cooler.

Look for a restriction in the oil passages of the oil cooler. If the oil cooler has a restriction, the oil temperature will be higher than normal when the engine is operated. The oil pressure of the engine will not get low just because the oil cooler has a restriction.

Also check the oil cooler bypass valve to see if it is held in the open position (unseated). This condition will let the oil through the valve instead of the oil cooler, and oil temperature will increase.

Gauges For Oil Pressure

An oil pressure gauge or a sender that has a defect can give an indication of low or high oil pressure.

The 1U5470 Engine Pressure Group can be used to make a comparison with instrument panel gauges.

Cooling System

This engine has a pressure type cooling system. A pressure type cooling system gives two advantages. The first advantage is that the cooling system can have safe operation at a temperature that is higher than the normal boiling (steam) point of water. The second advantage is that this type system prevents cavitation (low pressure bubbles suddenly made in liquids by mechanical forces) in the water pump. With this type system, it is more difficult for an air or steam pocket to be made in the cooling system.

The cause for increased engine temperature is generally because regular inspections of the cooling system were not made. Make a visual inspection of the cooling system before a test is made with test equipment.

Visual Inspection Of The Cooling System

1. Check coolant level in the cooling system.

2. Look for leaks in the system.

NOTE: Water pump seals. A small amount of coolant leakage across the surface of the "face-type" seals is normal, and required, to provide lubrication for this type of seal. A hole is provided in the water pump housing to allow this coolant/seal lubricant to drain from the pump housing. Intermittent leakage of small amounts of coolant from this hole is not an indication of water pump seal failure. Replace the water pump seals only if a large amount of leakage, or a constant flow of coolant is observed draining from the water pump housing. See the topic, Water Pump, Disassemble & Assemble, for a complete description of replacement of the water pump seals.

3. Look for bent radiator fins. Be sure that air flow through the radiator does not have a restriction.

4. Inspect the drive belt for the fan.

5. Check for damage to the fan blades.

6. Look for air or combustion gas in the cooling system.

7. Inspect the filler cap and the surface that seals the cap. This surface must be clean.

Testing the Cooling System

Remember that temperature and pressure work together. When a diagnosis is made of a cooling system problem, temperature and pressure must both be checked. Cooling system pressure will have an effect on cooling system temperatures. For an example, look at the chart to see the effect of pressure and height above sea level on the boiling (steam) point of water.

To check the cooling system, the coolant level must be to the correct level with the engine stopped and cold.

After the engine is cool, loosen the pressure cap and let the pressure out of the cooling system. Then remove the pressure cap.

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DO NOT loosen the filler or pressure cap on a hot engine. Steam or hot coolant can cause severe burns.

The level of the coolant should be within 13 mm (1/2 in) below the bottom of the fill pipe or to the proper level on the sight glass, if so equipped.

Test Tools For Cooling System

The 4C6500 Digital Thermometer Group is used in the diagnosis of over heating (engine hotter than normal) or overcooling (engine cooler than normal) problems. This group can be used to check temperatures in several different parts of the cooling system. The testing procedure is in Special Instruction, NEHS0554.

4C6500 Digital Thermometer Group

The 8T2700 Blowby/Air Flow Indicator Group is used to check the air flow through the radiator core. The test procedure is in Special Instruction, SEHS8712.

8T2700 Indicator Group

The 6V3121 Multitach Group is used to check the fan speed. The testing procedure is in Special Instruction, SEHS7807.

6V3121 Multitach Group

5P0957 or 5P3514 Coolant Tester

Check the coolant solution frequently in cold weather for glycol concentration with the 5P0957 or 5P3514 Coolant Tester to ensure adequate protection. Both testers are used for checking coolant freezing point, and are identical except temperature scale. They give immediate, accurate readings and can be used for antifreeze/coolants that contain etylene or propylene glycol.

Make Proper Antifreeze Additions

Adding pure antifreeze as a makeup solution for cooling system top-off is an unacceptable practice. It increases the concentration of antifreeze in the cooling system which increases the concentration of dissolved solids and undissolved chemical inhibitors in the cooling system. Add antifreeze mixed with acceptable water to the same freeze protection as your cooling system. Use the chart as follows to assist in determining the concentration of antifreeze to use.

Checking Pressure Cap

One cause for a pressure loss in the cooling system can be a defective seal on the radiator pressure cap.

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DO NOT loosen the filler or pressure cap on a hot engine. Steam or hot coolant can cause severe burns.

After the engine is cool, loosen the pressure cap and let the pressure out of the cooling system. Then remove the pressure cap.

Inspect the pressure cap carefully. Look for damage to the seal or to the surface that seals. Any foreign material or deposits on the cap, seal or surface that seals, must be removed.

Typical Schematic Of Pressure Cap
(A) Sealing surface of cap and radiator.

9S8140 Cooling System Pressurizing Pump Group

The 9S8140 Cooling System Pressurizing Pump Group is used to test pressure caps and to pressure check the cooling system for leaks.

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DO NOT loosen the filler or pressure cap on a hot engine. Steam or hot coolant can cause severe burns.

To check the pressure cap for the pressure that makes the pressure cap open, use the procedure that follows:

1. Remove the pressure cap from the radiator.

2. Put the pressure cap on the 9S8140 Cooling System Pressurizing Pump Group.

3. Look at the gauge for the exact pressure that makes the pressure cap open.

4. Make a comparison of the reading on the gauge with the correct pressure at which the pressure cap must open.

5. If the pressure cap is defective, install a new pressure cap.

Testing Radiator And Cooling System For Leaks

To test the radiator and cooling system for leaks, use the procedure that follows:

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DO NOT loosen the filler or pressure cap on a hot engine. Steam or hot coolant can cause severe burns.

1. Remove the pressure cap from the radiator.

2. Make sure the coolant is over the top of the radiator core.

3. Put the 9S8140 Cooling System Pressurizing Pump Group on the radiator.

4. Get the pressure reading on the gauge to 20 kPa (3 psi) more than the pressure on the pressure cap.

5. Check the radiator for outside leakage.

6. Check all connections and hoses for the cooling system for outside leakage.

7. If you do not see any outside leakage and the pressure reading on the gauge is still the same after five minutes, the radiator and cooling system does not have leakage. If the reading on the gauge goes down and you do not see any leakage, there is leakage on the inside of the cooling system. Make repairs as necessary.

Water Temperature Gauge Test

Test Location
(1) Plug.

Check the accuracy of the water temperature gauge if either of the conditions that follow are found:

1. The gauge reads normal, but the engine is too hot and a loss of coolant is found.

2. The gauge shows that the engine is hot, but no loss of coolant can be found.

Remove plug (1) and install the 4C6500 Digital Thermometer Group or the 2F7112 Thermometer. A temperature gauge of known accuracy can also be used to make this check.

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Work carefully around an engine that is running. Engine parts that are hot, or parts that are moving, can cause personal injury.

Start the engine and run it until the temperature reaches the desired range according to the test thermometer. If necessary, put a cover over part of the radiator or cause a restriction of the air flow. The reading on the gauge for water temperature should agree with test thermometer within the tolerance range of the gauge.

Water Temperature Regulator Test

1. Remove the regulator from the engine.

2. Heat water in a pan until the temperature is 98°C (208°F). Move the water around in the pan to make it all the same temperature.

3. Hang the regulator in the pan of water. The regulator must be below the surface of the water and it must be away from the sides and bottom of the pan.

4. Keep the water at the correct temperature for 10 minutes.

5. After ten minutes, remove the regulator and immediately measure the distance the regulator has opened. The distance must be a minimum of 9.5 mm (.37 in).

6. If the distance is less than 9.5 mm (.37 in), make a replacement of the regulator.

Water Pump Pressure Check

Typical Example-(1) Plug. (2) Coolant temperature sensor. (3) Water manifold assembly. (4) Water outlet. (5) Temperature regulator housing. (6) Bypass line. (7) Water pump. (8) Plug.

Water pump outlet pressure can be checked on water manifold assembly (3) next to the coolant temperature sensor (2). This check will determine if the water pump is operating correctly.

Remove plug (1) from water manifold assembly (3). Install the pressure gauge (9S8138) in the port and measure the pump pressure. The water pump pressure should be 100 to 125 kPa (15 to 18 psi).

A change in pressure can be measured between plug (1) on the water manifold assembly (4) and plug (8) on the inlet side of water pump (7).

Basic Block

Piston Rings

This engine has a top piston groove and ring of the KEYSTONE (taper) design. The 1U6431 Keystone Piston Ring Groove Gauge Group is available to check the top ring groove in the piston. Use the 8T3149 (#F) Gauge Assembly that is part of this Gauge Group to check the top ring groove on the piston. Refer to the instruction card for correct use of the 1U6431 Gauge Group.

Connecting Rods and Pistons

Use a 1U9593 Cylinder Pack Removal Group with a 1U6317 Bridge, and a 1U6319 Socket to remove a cylinder pack (connecting rod and piston) from the block. Use the 1U9788 Nylon Brush, or the 1U9787 Flex (hone) for reconditioning of the cylinder liners.

Use the 1U6683 Piston Ring Expander to remove or install piston rings.

Use the 1U6684 Piston Ring Compressor to install pistons into cylinder block.

Tighten the connecting rod nuts in the step sequence that follows:

1. Put 2P2506 Thread Lubricant on bolt threads and contact surfaces of nut and cap.

2. Tighten all nuts to 130 ± 7 N·m (95 ± 5 lb ft).

3. Put a mark on each nut and end of bolt.

4. Tighten each nut an additional 60 ± 5 degrees (1/6turn).

The connecting rod bearings fit tightly in the bore in the rod. If bearing joints or backs are worn (fretted), check bore size. This can be an indication of wear because of a loose fit.

Connecting Rod and Main Bearings

Connecting Rod Bearings

Connecting rod bearings are available with 0.508 mm (.0200 in) and .762 mm (.0300 in) smaller inside diameter than the original size bearings. These bearings are for crankshafts that have been "ground" (made smaller than the original size).

Main Bearings

Main bearings are available with 0.508 mm (.0200 in) and .762 mm (.0300 in) smaller inside diameter than the original size bearings. These bearings are for crankshafts that have been "ground" (made smaller than the original size).

Main bearings are also available with a larger outside diameter than the original size bearings. These bearings are for cylinder blocks that have had the bore for the main bearings "bored" (made larger than the original size). The size available is 0.508 mm (.0200 in) larger outside diameter than the original size bearings.

Cylinder Block

1P3537 Dial Bore Gauge Group

The bore in the block for main bearings can be checked with the main bearing caps installed without bearings. Tighten the nuts that hold the caps to the torque shown in the Specifications. Alignment error in the bores must not be more than 0.08 mm (.003 in).

Special Instruction, SMHS7606 gives instructions for the use of 1P4000 Line Boring Tool Group for alignment of the main bearing bores. The 1P3537 Dial Bore Gauge Group can be used to check the size of the bores. Special Instruction, GMG00981 is with the group.

Cylinder Liner Projection

NOTE: The use of conventional cylinder liner projection tooling can cause damage to the sealing surface of the aluminum spacer block.

1. Clean the cylinder liner flange and spacer block surface. Remove any nicks on the top of the spacer block.

Cylinder Liner Tooling
(1) 7X2558 Bolt. (2) 2S5658 Washer. (3) 8F1484 Washer. (4) 7K1977 Washer.

2. The illustration and chart identify the components required. An 8T0455 Cylinder Liner Projection Indicator Group is also required.

3. Assemble the components as shown in the illustration. The 7K1977 Washer (4) is made of a cotton fabric that is impregnated with resin. It will not damage the sealing surface of the block spacer.

NOTE: Inspect washer before measuring liner projection and replace if worn or damaged.

4. Tighten bolts (1) evenly as follows:

a. First tighten each bolt to 27 N·m (20 lb ft)

b. Tighten each bolt to 54 N·m (40 lb ft)

c. Tighten each bolt to 68 N·m (50 lb ft)

d. Tighten each bolt again to 68 N·m (50 lb ft)

8T0455 Liner Projection Tool Group
(5) 5S2671 Bolt. (6) 1P2403 Dial Indicator. (7) 1P2402 Gauge Body. (8) 1P5507 Gauge.

5. Loosen bolt (5) until dial indicator (6) can be moved. Place gauge body (7) and dial indicator (6) on the long side of gauge.

6. Slide dial indicator (6) down until the point contacts gauge (8) and moves the needle 1/4 revolution clockwise to a vertical position. Tighten bolt (5) and zero indicator.

(5) 5S2671 Bolt. (6) 1P2403 Dial Indicator. (8) 1P5507 Gauge.

7. Put gauge body (7) on the spacer plate, with the indicator point on the liner flange. Read the dial indicator to find the amount of liner projection. Check projection at four locations (90 degrees apart) around each cylinder liner. Liner projection must be 0.040 to 0.200 mm (.0016 to .0079 in). The maximum allowable difference between high and low measurements made at four places around each liner is 0.05 mm (.002 in). Difference in the average projection of the liners must not exceed 0.10 mm (.004 in) and difference in the average projection of adjacent liners should not exceed 0.05 mm (.002 in).

7. If a liner does not meet the liner projection specifications, check the thickness of the spacer block 100.00 ± 0.05 mm (3.937 ± 0.002 in) and the liner flange 100.12 ± 0.03 mm (3.942 ± 0.001 in) to determine if they are correct. If not within specification, replace and repeat the liner projection measurements.

Flywheel And Flywheel Housing

Face Run Out (axial eccentricity) of the Flywheel Housing

8T5096 Dial Indicator Group Installed (Typical Example)

If any method other than given here is used, always remember bearing clearance must be removed to get correct measurements.

1. Fasten a dial indicator to the flywheel so the anvil of the indicator will touch the face of the flywheel housing.

2. Put a force on the crankshaft toward the rear before the indicator is read at each point.

Checking Face Runout Of The Flywheel Housing

3. With dial indicator set at "0" (zero) at location (A), turn the flywheel and read the indicator at locations (B), (C) and (D).

4. The difference between lower and higher measurements taken at all four points must not be more than 0.38 mm (.015 in), which is the maximum permissible face run out (axial eccentricity) of the flywheel housing.

Bore Runout (radial eccentricity) of the Flywheel Housing

1. Fasten the dial indicator as shown so the anvil of the indicator will touch the bore of the flywheel housing.

2. With the dial indicator in position at (C), adjust the dial indicator to "0" (zero). Push the crankshaft up against the top of the bearing. Write the measurement for bearing clearance on line 1 in column (C) in the Chart For Dial Indicator Measurements.

8T5096 Dial Indicator Group Installed (Typical Example)

NOTE: Write the dial indicator measurements with their positive (+) and negative (-) notation (signs). This notation is necessary for making the calculations in the chart correctly.

3. Divide the measurement from Step 2 by 2. Write this number on line 1 in columns (B) & (D).

4. Turn the flywheel to put the dial indicator at (A). Adjust the dial indicator to "0" (zero).

5. Turn the flywheel counterclockwise to put the dial indicator at (B). Write the measurements in the chart.

Checking Bore Runout Of The Flywheel Housing

6. Turn the flywheel counterclockwise to put the dial indicator at (C). Write the measurement in the chart.

7. Turn the flywheel counterclockwise to put the dial indicator at (D). Write the measurement in the chart.

8. Add lines I & II by columns.

9. Subtract the smaller number from the larger number in line III in columns (B) & (D). The result is the horizontal eccentricity (out of round). Line III, column (C) is the vertical eccentricity.

10. On the graph for total eccentricity, find the point of intersection of the lines for vertical eccentricity and horizontal eccentricity.

11. If the point of intersection is in the range marked "Acceptable", the bore is in alignment. If the point of intersection is in the range marked "Not Acceptable", the flywheel housing must be changed.

Graph For Total Eccentricity

Face Runout (axial eccentricity) of the Flywheel.

1. Install the dial indicator as shown. Always put a force on the crankshaft in the same direction before the indicator is read so the crankshaft end clearance (movement) is always removed.

Checking Face Runout Of The Flywheel (Typical Example)

2. Set the dial indicator to read "0" (zero).

3. Turn the flywheel and read the indicator every 90 degrees.

4. The difference between the lower and higher measurements taken at all four points must not be more than 0.15 mm (.006 in), which is the maximum permissible face runout (axial eccentricity) of the flywheel.

Bore Runout (radial eccentricity) of the Flywheel

1. Install the dial indicator (3) and make an adjustment of the universal attachment (4) so it makes contact as shown.

2. Set the dial indicator to read "0" (zero).

3. Turn the flywheel and read the indicator every 90 degrees.

4. The difference between the lower and higher measurements taken at all four points must not be more than 0.15 mm (.006 in), which is the maximum permissible bore runout (radial eccentricity) of the flywheel.

5. Runout (eccentricity) of the bore for the pilot bearing for the flywheel clutch, must not exceed 0.13 mm (.005 in).

Checking Bore Runout Of The Flywheel (Typical Example)
(1) 7H1945 Holding Rod. (2) 7H1645 Holding Rod. (3) 7H1942 Indicator. (4) 7H1940 Universal Attachment.

Checking Flywheel Clutch Pilot Bearing Bore

Vibration Damper

Damage to or failure of the damper will increase vibrations and result in damage of the crankshaft. It will cause more gear train noise at variable points in the speed range.

If the damper is bent or damaged, or if the bolt holes in the damper are loose fitting, replace the damper. Replacement of the damper is also needed at the time of a crankshaft failure due to torsional forces.

1. Install a dial indicator, contact point and other parts as necessary to hold the dial indicator stationary. The contact point must be perpendicular (at a 90 degree angle) to the face of the outer ring of the damper, and must make contact approximately at the center of the outer ring.

2. Push on the front end of the crankshaft so the end play (free movement on the centerline) is removed. Keep the crankshaft pushed back until the measurements are done.

3. Adjust the dial indicator to zero.

4. Turn the crankshaft 360 degrees and watch the dial indicator. A total indicator reading of 0.00 to 2.03 mm (.000 to .080 in) is acceptable.

Electrical System

Test Tools For Electrical System

Most of the tests of the electrical system can be done on the engine. The wiring insulation must be in good condition, the wire and cable connections must be clean and tight, and the battery must be fully charged. If the on-engine test shows a defect in a component, remove the component for more testing.

The service manual Testing And Adjusting Electrical Components, REG00636 has complete specifications and procedures for the components of the starting circuit and the charging circuit.

4C4911 Battery Load Tester

The 4C4911 Battery Load Tester is a portable unit in a metal case for use under field conditions and high temperatures. It can be used to load test all 6, 8 and 12V batteries. This tester has two heavy-duty load cables that can easily be fastened to the battery terminals. A load adjustment knob on the top permits the current being drawn from the battery to be adjusted to a maximum of 1000 amperes. The tester is cooled by an internal fan that is automatically activated when a load is applied.

The tester has a built in LCD digital voltmeter and amperage meter. The digital voltmeter accurately measures the battery voltage at the battery through tracer wires buried inside the load cables. The digital amperage meter accurately displays the current being drawn from the battery under test.

NOTE: Make reference to Operating Manual, SEHS9249 for more complete information for use of the 4C4911 Battery Load Tester.

8T0900 AC/DC Clamp-On Ammeter

The 8T0900 AC/DC Clamp-On Ammeter is a completely portable, self-contained instrument that allows electrical current measurements to be made without breaking the circuit or disturbing the insulation on conductors. A digital display is located on the ammeter for reading current directly in a range from 1 to 1200 amperes. If an optional 6V6014 Cable is connected between this ammeter and one of the digital multimeters, current readings of less than 1 ampere can then be read directly from the display of the multimeter.

A lever is used to open the jaws over the conductor [up to a diameter of 19 mm (.75 in)], and the spring loaded jaws are then closed around the conductor for current measurement. A trigger switch that can be locked in the ON or OFF position is used to turn on the ammeter. When the turn-on trigger is released, the last current reading is held on the display for five seconds. This allows accurate measurements to be taken in limited access areas where the digital display is not visible to the operator. A zero control is provided for DC operation, and power for the ammeter is supplied by batteries located inside the handle.

NOTE: Make reference to Special Instruction, SEHS8420 for more complete information for use of the 8T0900 Clamp-On Ammeter.

6V7070 Heavy-Duty Digital Multimeter

The 6V7070 Heavy-Duty Digital Multimeter is a completely portable, hand held instrument with a digital display. This multimeter is built with extra protection against damage in field applications, and is equipped with seven functions and 29 ranges. The 6V7070 Multimeter has an instant ohms indicator that permits continuity checking for fast circuit inspection. It also can be used for troubleshooting small value capacitors.

The 6V7800 Regular-Duty Digital Multimeter (a low cost option to the Heavy-Duty Multimeter) is also available; however, the 6V7800 Multimeter does not have the 10A range or the instant ohms feature of the 6V7070 Multimeter.

NOTE: Make reference to Special Instruction, SEHS7734 for complete information for use of the 6V7070 and 6V7800 Multimeters.

Electronic Service Tools

The Caterpillar ECAP Service Tool for the 3176B Electronic Control system is designed to help the service technician analyze and locate faults or problems within the system. It is required to perform some sensor calibrations electronically, and to read or change engine parameters. The basic tool has small plug in modules, called Service Program Modules (SPM), to adapt the basic tool to the specific Caterpillar electronic control application.

The Electronic Control Analyzer Programmer (ECAP) communicates with the 3176B Electronic Control Module to read Diagnostic Codes, to read the various sensor output signals such as engine rpm or boost pressure, and controls electronic calibration of the 3176B sensors through the ECM.

The ECAP (requires PWM adapter to measure at the sensor) can measure Pulse Width Modulated (PWM) signals, such as the signal produced by the Throttle Position Sensor. The ECAP is required when entering Factory Passwords.

There are several adapter cables, breakout "T" cables, probes, etc., that are used with the service tools in order to gain access for measurements of wires carrying voltages and signals. Both heavy duty multimeter and the standard duty multimeter are suitable for making the necessary measurements. Other Special Tools include those needed to measure pressure or temperature.

Battery

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Never disconnect any charging unit circuit or battery circuit cable from the battery when the charging unit is operated. A spark can cause an explosion from the flammable vapor mixture of hydrogen and oxygen that is released from the electrolyte through the battery outlets. Injury to personnel can be the result.

The battery circuit is an electrical load on the charging unit. The load is variable because of the condition of the charge in the battery. Damage to the charging unit will result if the connections (either positive or negative) between the battery and charging unit are broken while the charging unit is in operation. This is because the battery load is lost and there is an increase in charging voltage. High voltage will damage, not only the charging unit, but also the regulator and other electrical components.

Use the 4C4911 Battery Load Tester to load test a battery that does not hold a charge when in use. Refer to Operating Manual, SEHS9249 for more detailed instructions on use of the 4C4911 Battery Load Tester. See Special Instruction, SEHS7633, Battery Test Procedure, for the correct procedure and specifications to use when testing batteries.

Charging System

The condition of charge in the battery at each regular inspection will show if the charging system operates correctly. An adjustment is necessary when the battery is constantly in a low condition of charge or a large amount of water is needed (more than one ounce of water per cell per week or per every 100 service hours).

When it is possible, make a test of the charging unit and voltage regulator on the engine, and use wiring and components that are a permanent part of the system. Off-engine (bench) testing will give a test of the charging unit and voltage regulator operation. This testing will give an indication of needed repair. After repairs are made, again make a test to give proof that the units are repaired to their original condition of operation.

To check for correct output of the alternator, see the Specifications module.

For complete service information, refer to Service Manual Module, SENR3862. This module is part of REG00636 Service Manual.

Before the start of on-engine testing, the charging system and battery must be checked as shown in the Steps that follow:

1. Battery must be at least 75% (1.225 Sp.Gr.) fully charged and held tightly in place. The Battery holder must not put too much stress on the battery.

2. Cables between the battery, starter and engine ground must be the correct size. Wires and cables must be free of corrosion and have cable support clamps to prevent stress on battery connections (terminals).

3. Leads, junctions, switches, and panel instruments that have direct relation to the charging circuit must give correct circuit control.

4. Inspect the drive components for the charging unit to be sure they are free of grease and oil and have the ability to operate the charging unit.

Alternator Regulator Adjustment

When an alternator is charging the battery too much or not enough, the charging rate of the alternator should be checked. Make reference to the Specifications module to find all testing specifications for the alternators and regulators.

Alternator
(1) Ground terminal. (2) Pulley nut.

No adjustment can be made to change the rate of charge on the alternator regulators. If rate of charge is not correct, a replacement of the regulator is necessary.

Alternator Pulley Nut Tightening

Tools To Tighten Alternator Pulley Nut
(1) 8T9293 Torque Wrench. (2) 8S1588 Adapter (1/2 inch female to 3/8 inch male). (3) 2P8267 Socket Assembly. (4) 8H8517 Combination Wrench (1-1/8 inch). (5) 8T5314 Socket.

Tighten nut that holds the pulley to a torque of 100 ± 7 N·m (75 ± 5 lb ft) with the tools shown.

Starting System

Use the multimeter in the DCV range to find starting system components which do not function.

Move the start control switch to activate the starter solenoid. Starter solenoid operation can be heard as the pinion of the starter motor is engaged with the ring gear on the engine flywheel.

If the solenoid for the starter motor will not operate, it is possible that the current from the battery did not get to the solenoid. Fasten one lead of the multimeter to the connection (terminal) for the battery cable on the solenoid. Put the other lead to a good ground. A zero reading is an indication that there is a broken circuit from the battery. More testing is necessary when there is a voltage reading on the multimeter.

The solenoid operation also closes the electric circuit to the motor. Connect one lead of the multimeter to the solenoid connection (terminal) that is fastened to the motor. Put the other lead to a good ground. Activate the starter solenoid and look at the multimeter. A reading of battery voltage shows the problem is in the motor. The motor must be removed for further testing. A zero reading on the multimeter shows that the solenoid contacts do not close. This is an indication of the need for repair to the solenoid or an adjustment to be made to the starter pinion clearance.

Make a test with one multimeter lead fastened to the connection (terminal) for the small wire at the solenoid and the other lead to the ground. Look at the multimeter and activate the starter solenoid. A voltage reading shows that the problem is in the solenoid. A zero reading is an indication that the problem is in the start switch or the wires for the start switch.

Fasten one multimeter lead to the start switch at the connection (terminal) for the wire from the battery. Fasten the other lead to a good ground. A zero reading indicates a broken circuit from the battery. Make a check of the circuit breaker and wiring. If there is a voltage reading, the problem is in the start switch or in the wires for the start switch.

A starter motor that operates too slow can have an overload because of too much friction in the engine being started. Slow operation of the starter motor can also be caused by a short circuit, loose connections and/or dirt in the motor.

To check for correct output of starter motors and starter solenoid, see the Specifications module.

For complete service information, refer to Service Manual Module, SENR3581. This module is part of REG00636 Service Manual.

Pinion Clearance Adjustment

When the solenoid is installed, make an adjustment of the pinion clearance. The adjustment can be made with the starter motor removed.

Typical Connection for Checking Pinion Clearance
(1) Connector from MOTOR terminal on solenoid to motor. (2) SW terminal (3) Ground terminal.

1. With the solenoid installed on the starter motor, remove connector (1).

2. Connect a battery, of the same voltage as the solenoid, to the terminal (2), marked SW.

3. Connect the other side of the battery to ground terminal (3).

4. Connect for a moment a wire from the solenoid connection (terminal) marked Motor to the ground connection (terminal). The pinion will shift to crank position and will stay there until the battery is disconnected.

Typical Pinion Clearance Adjustment
(4) Shaft nut. (5) Pinion. (6) Pinion clearance.

5. Push the pinion toward the commulator end to remove free movement.

6. Pinion clearance (6) must be 8.3 to 9.9 mm (.33 to .39 in).

7. To adjust pinion clearance, remove plug and turn nut (4).

8. After the adjustment is completed, install the plug over adjustment nut (4) and install connector (1) between the MOTOR terminal on the solenoid and the starter motor.