C9.3 Marine Generator Set Engines Caterpillar

The engine oil pressure may be checked electronically by using the Caterpillar Electronic Technician (ET). The engine oil pressure can be measured with Cat ET. Refer to Troubleshooting for information on the use of the Cat ET.

Measuring Engine Oil Pressure

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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.

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NOTICE
Keep all parts clean from contaminants. Contaminants may cause rapid wear and shortened component life.

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NOTICE
Care must be taken to ensure that fluids are contained during performance of inspection, maintenance, testing, adjusting, and repair of the product. Be prepared to collect the fluid with suitable containers before opening any compartment or disassembling any component containing fluids. Refer to Special Publication, NENG2500, "Dealer Service Tool Catalog" for tools and supplies suitable to collect and contain fluids on Cat products. Dispose of all fluids according to local regulations and mandates.

Table 1

Required Tools
Tool	Part Number	Part Name	Quantity
A	1U-5470 or 198-4240	Engine Pressure Group or Pressure Indicator Tool Group	1

Illustration 1	g00296486
1U-5470 Engine Pressure Group

Tool (A) measures the oil pressure in the system. This engine tool group can read the oil pressure inside the oil manifold.

Note: Refer to Special Instruction, SEHS8907, "Using the 1U-5470 Engine Pressure Group" for more information. Refer to Operating Manual, NEHS0818, "Using the 198-4240 Pressure Indicator Tool Group" for more information.

1. Start the engine. Run the engine with the correct oil. Refer to Operation and Maintenance Manual, "Refill Capacities and Recommendations" for the recommendations of engine oil.

   Note: Engine oil pressure to the camshaft and main bearings should be checked on each side of the cylinder block at the oil gallery.

2. Record the values of the engine oil pressure when the engine is at operating temperature 100 °C (212 °F) at low idle and at 1800 rpm.

   Note: The recorded oil pressure readings must be above the readings that are listed below.

   C9 - The engine oil pressure should be 48 kPa (7 psi) to 152 kPa (22 psi)

   C13 - The engine oil pressure should be 53 kPa (8 psi) to 242 kPa (35 psi)

   C15/18 - The engine oil pressure should be 107 kPa (15 psi) to 278 kPa (40 psi)

3. Check the Engine Oil Pressure for the Left Oil Gallery at the Oil Pressure Sensor

   1. Remove the oil pressure sensor.

   2. Install a pipe "T" in the pressure sensor port.

   3. Install Tool (A) on one side of the pipe "T". Install the oil pressure sensor on the other side of the pipe "T".

   4. Start the engine and compare the two readings. The pressure reading must be within ±13.8 kPa (±2 psi).

   5. If the pressure is within ±13.8 kPa (±2 psi), the sensor is good.

   6. If the pressure is not within ±13.8 kPa (±2 psi), replace the sensor.

   7. Remove Tool (A) and return the sensor to the pressure sensor port.

4. Check the Engine Oil Pressure for the Right Oil Gallery at the NRS Exhaust Valve
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   Illustration 2	g02168213
   (1) NRS exhaust valve (2) Oil line

   1. Record the value of the engine oil pressure when the engine is at operating temperature 100 °C (212 °F) at 1800 rpm and at low idle.

   2. Remove the oil supply line (2) from the NRS exhaust valve (1).

   3. Install a pipe "T" into the port of the oil supply line.

   4. Install Tool (A) on one side of the pipe "T". Install the oil supply line on the other side of the pipe "T".

5. After recording the oil pressures, remove Tool (A) and return the oil supply line to the NRS exhaust valve port.

6. Compare the recorded engine oil pressures with the oil pressure indicators on the instrument panel and the engine oil pressure that is displayed on Cat ET.

7. An engine oil pressure indicator or an engine oil pressure sensor that has a defect can give a false indication of a low or high oil pressure. If there is a notable difference between the engine oil pressure readings, make necessary repairs.

8. If low engine oil pressure is determined, refer to "Reasons for Low Engine Oil Pressure".

9. If high engine oil pressure is determined, refer to "Reason for High Engine Oil Pressure".

Reasons for Low Engine Oil Pressure

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NOTICE
Keep all parts clean from contaminants. Contaminants may cause rapid wear and shortened component life.

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NOTICE
Care must be taken to ensure that fluids are contained during performance of inspection, maintenance, testing, adjusting, and repair of the product. Be prepared to collect the fluid with suitable containers before opening any compartment or disassembling any component containing fluids. Refer to Special Publication, NENG2500, "Dealer Service Tool Catalog" for tools and supplies suitable to collect and contain fluids on Cat products. Dispose of all fluids according to local regulations and mandates.

• Engine oil level is low. Refer to "Engine Oil Level" in Troubleshooting, "Oil Pressure Is Low".

• Engine oil is contaminated. Refer to Step 1.

• The engine oil bypass valves are open. Refer to "Oil Filter Bypass" in Troubleshooting, "Oil Pressure Is Low".

• The engine lubrication system is open. Refer to Step 2.

• The oil pickup tube has a leak or a restricted inlet screen. Refer to Step 3.

• The engine oil pump is faulty. Refer to Step 4 and to "Oil Pump" in Troubleshooting, "Oil Pressure Is Low".

• Engine bearings have excessive clearance. Refer to "Worn Engine Components" in Troubleshooting, "Oil Pressure Is Low".

1. Engine oil that is contaminated with fuel or coolant will cause low engine oil pressure. High engine oil level in the crankcase can be an indication of contamination. Determine the reason for contamination of the engine oil and make the necessary repairs. Replace the engine oil with the approved grade of engine oil. Refer to Operation and Maintenance Manual, "Engine Oil" for the recommendations of engine oil.
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   NOTICE
   Caterpillar oil filters are built to Caterpillar specifications. Use of an oil filter not recommended by Caterpillar could result in severe engine damage to the engine bearings, crankshaft, etc., as a result of the larger waste particles from unfiltered oil entering the engine lubricating system. Only use oil filters recommended by Caterpillar.

2. An oil line or an oil passage that is open, broken, or disconnected will cause low engine oil pressure. An open lubrication system could be caused by a piston cooling jet that is missing or damaged. Determine the reason for an open lubrication system of the engine and make the necessary repairs.

   Note: The piston cooling jets direct engine oil toward the bottom of the piston in order to cool the piston. The piston cooling jets also provide lubrication for the piston pin. Breakage, a restriction, or an incorrect installation of the piston cooling jets will cause seizure of the piston.

3. The inlet screen of the oil pickup tube for the engine oil pump can have a restriction. This restriction will cause cavitation and a loss of engine oil pressure. Check the inlet screen on the oil pickup tube and remove any material that may be restricting engine oil flow. Low engine oil pressure may also be the result of the oil pickup tube that is drawing in air. Check the joints of the oil pickup tube for cracks or a damaged O-ring seal. Remove the engine oil pan in order to gain access to the oil pickup tube and the oil screen. Refer to Disassembly and Assembly, "Engine Oil Pan - Remove and Install" for more information.

4. Check the following problems that may occur to the engine oil pump.

   1. Air leakage in the supply side of the oil pump will also cause cavitation and loss of oil pressure. Check the supply side of the oil pump and make necessary repairs. For information on the repair of the engine oil pump, refer to Disassembly and Assembly, "Engine Oil Pump - Remove".

   2. Oil pump gears that have too much wear will cause a reduction in oil pressure. Repair the engine oil pump. For information on the repair of the engine oil pump, refer to Disassembly and Assembly, "Engine Oil Pump - Remove".

Reason for High Engine Oil Pressure

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NOTICE
Keep all parts clean from contaminants. Contaminants may cause rapid wear and shortened component life.

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NOTICE
Care must be taken to ensure that fluids are contained during performance of inspection, maintenance, testing, adjusting, and repair of the product. Be prepared to collect the fluid with suitable containers before opening any compartment or disassembling any component containing fluids. Refer to Special Publication, NENG2500, "Dealer Service Tool Catalog" for tools and supplies suitable to collect and contain fluids on Cat products. Dispose of all fluids according to local regulations and mandates.

Engine oil pressure will be high if the engine oil bypass valves become stuck in the closed position and the engine oil flow is restricted. Foreign matter in the engine oil system could cause a restriction of the oil flow and the movement of the engine oil bypass valves. If the engine oil bypass valves are stuck in the closed position, replace the oil filter base. Install new engine oil filters. New engine oil filters will prevent more debris from causing this problem.

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NOTICE
Caterpillar oil filters are built to Caterpillar specifications. Use of an oil filter not recommended by Caterpillar could result in severe engine damage to the engine bearings, crankshaft, etc., as a result of the larger waste particles from unfiltered oil entering the engine lubricating system. Only use oil filters recommended by Caterpillar.