D346 MARINE ENGINE Caterpillar


Engine Lubrication System

Usage:



Diesel Engine Lube Oil

Checking Oil Pressure Gauge Reading

After starting and during operation, frequently observe the oil pressure gauge. If the gauge indicator registers below "NORMAL", or if the indicator fluctuates, check the oil level and take corrective measures.

Checking Oil Level

Check the oil level with the engine idling. Oil level must be between the ADD and FULL marks on the oil level gauge. Add oil as required. See Lubrication and Maintenance Chart for proper oil.


CHECKING CRANKCASE OIL LEVEL

Draining Crankcase Lube Oil

With engine stopped and oil warm:

1. Wipe dirt from the right hand oil filter housing cover.
2. Remove the vent plug.
3. Open the oil filter housing drain valve.


VENT PLUG AND DRAIN VALVE

4. Remove the oil cooler drain plug.


OIL COOLER DRAIN PLUGS

5. Remove the oil pan drain plug.


OIL PAN DRAIN PLUG

If a sump pump is used:

a. Connect a suitable drain to the pump outlet.


SUMP PUMP VALVES AND PUMP OUTLET

b. Open the valve to the engine crankcase.
c. Close the valve to the marine gear housing.
d. Operate the sump pump handle until the crankcase is empty.
e. Close the valve to the engine crankcase.

Cleaning Breather(s) (D379, D398, D399 Engines)

1. D399 Engine Only: Loosen the front hose clamp from the breather tube.


LOOSENING HOSE CLAMP

2. All Engines: Remove breather mounting bolts. Lift off breathers.


REMOVING BREATHERS

3. D399 Engine Only: Remove and inspect the upper and lower hoses from the breathers.
4. All Engines: Wash the breather(s) in clean diesel fuel or solvent.
5. All Engines: Install breather(s).
6. D399 Engine Only: Install lower and upper hose. Tighten all clamps. Connect breather tube.

Cleaning Breather(s) (D346, D348, D349 Engines)

One breather is mounted on the left front valve cover. On D349 Engines, a second breather is mounted on the right rear valve cover. Service both breathers when so equipped.

1. Loosen the hose clamp.


LOOSENING HOSE CLAMP

2. Loosen the cover bolt and lift off the breather cover.


REMOVING THE BREATHER COVER

3. Remove and inspect breather element.


REMOVING BREATHER ELEMENT

4. Wash breather element in clean diesel fuel or kerosene.
5. Install breather element and cover. Connect hose.

Oil Filter Service Indicator

Checking Oil Filter Change Indicator

When the engine is operating under full load with the oil at operating temperature, observe the position of the red plunger of the indicator. When the plunger rises approximately half the height of the plastic window, install new oil filter elements.


OIL FILTER SERVICE INDICATOR (Filter housing)


OIL FILTER SERVICE INDICATOR (Left cover)

If the normal oil filter period occurs before the plunger rises, change the oil filter elements at that time. See the LUBRICATION CHART for the oil filter change period.

Oil Filter Elements

Installing Oil Filter Elements

If your engine is equipped with a standard oil filter system, read the following instructions. If your engine is equipped to permit changing the oil filter elements while the engine is running, read the topic, "DUPLEX OIL FILTER SYSTEM".

Installing Oil Filter Elements

1. Drain the oil filter housing.


VENT PLUG AND DRAIN VALVE

2. Remove the right hand cover from the filter housing.


OIL FILTER HOUSING COVER

3. Remove the oil filter elements.


REMOVING OIL FILTER ELEMENTS

4. Wipe the oil filter housing with a clean rag.
5. Install new filter elements, and the filter housing cover.
6. Close the filter housing drain valve.
7. Fill the oil filter housing and oil cooler with oil; add the oil through the vent plug opening. See the LUBRICATION AND MAINTENANCE CHART for proper oil to use. Do not try to overfill; the excess oil will return through the oil lines to the engine crankcase.
8. Install the vent plug.
9. Fill the crankcase to the FULL mark on the oil level gauge.
10. Prelubricate the engine oil system, if equipped to do so:

D349 and D399 Engines: When the START switch is energized, the prelube pump will develop oil pressure in the engine before the starting motors are energized.


PRELUBE PUMP - D349 and D399 Engines

D346, D348, D379 and D398 Engines equipped with a sump pump: The sump pump can be used as a prelube pump by connecting a line from the outlet of the sump pump, through a threeway valve into the oil cooler bypass line.


SUMP PUMP CONNECTED AS PRELUBE PUMP

11. Start the engine; reduce engine speed to low idle. Observe the oil pressure gauge reading.

If oil pressure does not register, the low oil pressure shut-off control will stop the engine in approximately seven seconds.

If the low oil pressure shut-off control stops the engine, investigate the cause and make repairs before attempting to restart.

12. Reduce engine speed to low idle. Observe the oil pressure gauge. Oil pressure must be indicated, or shut the engine down and investigate the cause.
13. Allow the engine to reach operating temperatures.
14. Check the oil level with the engine running. Oil level should be between the ADD mark and the FULL mark. Add oil if necessary.

Duplex Oil Filter System

Duplex Oil Filter System

Marine propulsion engines and marine auxiliary electric set engines, which operate under the jurisdiction of international marine classification societies, are required to be equipped with a duplex oil filter system. The duplex oil filter system permits changing oil filter elements without stopping the engine.

The filter elements, located in the horizontal oil filter housing, filter the oil during normal operation. The two oil filter cans, located on the right side of the engine, are auxiliary filter elements. At the specified oil filter element change interval, or when the oil filter change indicator is raised approximately one half its maximum height, move the selector lever so as to divert the crankcase oil through the two auxiliary filter elements while the main filter elements are changed.

Installing New Main Filter Elements

The main oil filter elements may be changed with the engine running as follows:

1. Push down and hold the fill valve to insure that the auxiliary oil filter housing is filled with oil. When the indicated filter pressure stops rising, release the fill valve.


FILL VALVE AND FILTER PRESSURE GAUGES

2. Move the selector lever 90° in a clockwise motion to the auxiliary filter position. The crankcase oil is now being filtered through the auxiliary oil filter elements.


SELECTOR LEVER-AUXILIARY FILTER POSITION

3. Open the main filter drain valve.
4. Remove the vent plug from the right hand end cover and allow the filter housing to drain.


VENT PLUG AND DRAIN

5. Remove the right hand housing cover.

------ WARNING! ------

Protect hands to avoid injury from hot oil or hot engine parts. Photographs show bare hands only for illustrative purposes.

------WARNING!--------
6. Remove the used filter elements from the filter housing.


REMOVING OIL FILTER HOUSING COVER

7. Wipe sediment from inside the filter housing using clean cloth.
8. Install new filter elements.
9. Inspect the cover gasket. Install a new gasket if necessary.


INSTALLING NEW ELEMENTS AND GASKET

10. Install the filter housing cover.
11. Close the drain valve, install the vent plug.
12. Push down and hold the fill valve until the indicated filter pressure stops rising; then release the fill valve.


NOTICE

The oil must force the air out of the main filter housing to prevent air from later entering the oil lines and engine bearings.



FILLER VALVE AND OIL PRESSURE GAUGES

13. Move the selector lever 90° in a counterclockwise motion to the main filter position. The crankcase oil is now being filtered through the main oil filter elements.


SELECTOR LEVER-NORMAL OPERATION


NOTICE

For long periods of running, the selector lever must be turned so it is parallel with the engine. If the selector lever remains positioned at right angle to the engine, only two filter elements will be filtering the engine crankcase oil instead of five. Early plugging of these two elements will result, and dirty oil will be by-passed through the engine.


14. Check for oil leaks.

Servicing The Auxiliary Oil Filter Elements

The auxiliary oil filter elements should be changed after each main oil filter change. This will insure that clean auxiliary filter elements are available for emergency use at all times. The auxiliary oil filter elements may be changed with the engine running as follows:

1. Service the auxiliary filter elements during normal operation with the selector lever pointed forward


SELECTOR LEVER-NORMAL OPERATION

2. Wipe dirt from each auxiliary oil filter housing.
3. Remove the auxiliary oil filter housing drain plugs.
4. Loosen each filter housing mounting bolt.


AUXILIARY OIL FILTERS

5. Remove each housing and element.

------ WARNING! ------

Protect hands to avoid injury from hot oil or hot engine parts. Photographs show bare hands only for illustrative purposes.

------WARNING!--------


REMOVING AUXILIARY FILTER HOUSING AND ELEMENT

6. Remove the gasket from each filter housing base.
7. Remove the element from each filter housing, and wipe the inside of the housing with a clean rag.
8. Install new gaskets.
9. Install a new element into each housing.
10. Install the filter housings to the filter bases.
11. Install the drain plugs.
12. Push down and hold the fill valve until the indicated filter pressure stops rising; then release the fill valve.


NOTICE

The air must be removed from the auxiliary filter housings to prevent air from later entering the oil lines and engine bearings.



FILL VALVE AND FILTER PRESSURE GAUGE

13. Move the selector lever 90° in a clockwise motion to the auxiliary filter position. Check for oil leaks.


SELECTOR LEVER - AUXILIARY FILTER POSITION

14. After determining the auxiliary filter system is ready for use, move the selector lever 90° in a counterclockwise motion to the main filter position.


SELECTOR LEVER - MAIN FILTER POSITION

15. Continue running on the main filters until they require changing. Then follow the instructions for installing new main oil filter elements.


NOTICE

For long periods of running, the selector lever must be turned parallel with the engine crankshaft. With the selector lever at right angles to the engine, only two filter elements will be used instead of five elements. Early filter element plugging will result.


Prelube Pump
(D349 and D399 Engines)

When the START switch is energized, the prelube pump will build oil pressure in the engine lubrication system before the starting motors are energized.

A prelube pump with grease plugs on the rear bearing and a separate lube system for the prelube pump reduction drive, as shown in these photos, requires servicing as follows:

Checking Prelube Pump Oil Level

Check the pre-lube gear case oil level before starting the diesel engine. Oil level must be between the LOW and HIGH marks on the bayonet gauge. Add oil as required. See Lubrication and Maintenance Chart for proper oil.


CHECKING OIL LEVEL

Draining Pre-Lube Pump Oil

1. Remove drain plug and drain oil.


FILLER AND DRAIN PLUGS

2. Flush the gear case with diesel fuel or kerosene.
3. Fill gear case with oil. See Lubrication and Maintenance Chart for proper oil.

Lubricating Pre-Lube Pump Rear Bearing

1. Remove the rear bearing grease plug.


REMOVING GREASE PLUG

2. Clean out old grease.
3. Install a grease fitting. Lubricate; see Lubrication and Maintenance Chart for proper grease.
4. Remove the grease fitting.
5. Move the compression release lever to START to prevent the engine from starting.


COMPRESSION RELEASE LEVER (1 each bank)

6. Turn the start switch to START; the running pre-lube pump motor will push the excess grease out the plug hole.
7. Wipe excess grease from outside of motor.
8. Clean and install the grease plug.
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