C27 and C32 Tier 4 Engines Caterpillar

Note: Severe slopes can cause low oil pressure. The oil level in the engine crankcase must be at the "FULL" mark on the dipstick. Refer to Operation and Maintenance Manual for details.

Use this procedure in order to troubleshoot low engine oil pressure. Use this procedure if one of the following event codes is active. Access the engine monitoring system on Caterpillar Electronic Technician (ET) in order to view the current trip points for these codes. Refer to Troubleshooting, "Engine Monitoring Parameters" for information about engine events.

Table 1

Engine Event
J1939 Code and Description	Conditions that Generate the Code	System Response
100-1 Engine Oil Pressure : Low - most severe (3)	Oil pressure is below the specified pressure for at least eight seconds. A snapshot is triggered. The code is logged. Engine performance is not affected.	The code is logged.
100-17 Engine Oil Pressure : Low - least severe (1)	Oil pressure is lower than the specified pressure for at least four seconds. Engine power is reduced. A snapshot is triggered. The code is logged. Factory passwords are required.
100-18 Engine Oil Pressure : Low - moderate severity (2)

Probable Causes

Engine Oil Level

• Low engine oil level

Aerated Oil

• Aeration in the oil

Oil Viscosity

• Low oil viscosity

Oil Filter

• Plugged Oil Filter

Oil Pump

• Faulty oil pump

Engine Oil Pressure Sensor

• Faulty engine oil pressure sensor

Engine Oil Filter Bypass Valve

• Faulty bypass valve

Oil Pump Suction Tube

• Damaged suction tube or cracked suction tube

Worn Engine Components

• Excessive wear of engine components

Troubleshooting Sequence

Note: Complete the following procedures in the order that is provided.

1. Engine Oil Level

   1. Check the engine oil level in the crankcase. Refer to the Operation and Maintenance Manual for calibration of the dipstick gauge. The oil level can possibly be too far below the oil pump supply tube. There will not be enough oil and the oil pump will not supply enough lubrication to the engine components.

   2. If the engine oil level is low, add engine oil in order to obtain the correct level. Refer to Operation and Maintenance Manual, "Engine Oil" for the recommendations of engine oil.

   3. If the problem has been corrected, return the unit to service.

   4. If the symptom remains, proceed to the next Test Step.

2. Aerated Oil

   1. Sample the engine oil for aeration.

   2. If the oil is aerated, proceed to Test Step 8.

   3. If the symptom remains, proceed to the next Test Step.

3. Oil Viscosity

   1. Sample the engine oil viscosity.

   2. If the oil viscosity is not correct, replace the engine oil. Refer to Operation and Maintenance Manual, "Engine Oil" for the recommendations of engine oil. If the symptom is corrected, return the unit to service. If the symptom still exists, proceed to the next Test Step.

   3. If the oil viscosity is correct, proceed to the next Test Step. Refer to Operation and Maintenance Manual, "Engine Oil" for the recommendations of engine oil.

4. Oil Filter

   1. Replace the engine oil filter.

   2. If the symptom is corrected, return the unit to service.

   3. If the symptom remains, proceed to the next Test Step.

5. Oil Pump

   1. Manually check the engine oil pressure. Refer to Testing and Adjusting, "Engine Oil Pressure - Test" for the correct procedure.

   2. If the pressure at the test port is correct, proceed to the next Test Step.

   3. If the pressure does not meet the specifications, replace the pump.

   4. If the symptom is corrected, return the unit to service.

   5. If the symptom remains, proceed to the next Test Step.

6. Engine Oil Pressure Sensor

   1. Remove the oil pressure sensor.

   2. Install a tee fitting at the port for the pressure sensor.

   3. Install a manual gauge on one side of the tee fitting and install the oil pressure sensor on the other side of the tee fitting.

   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), proceed to the next Test Step.

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

   7. If the symptom is corrected, return the unit to service.

   8. If the symptom remains, proceed to the next Test Step.

7. Engine Oil Filter Bypass Valve

   1. Replace the oil filter base.

   2. If the symptom is corrected, return the unit to service.

   3. If the symptom remains, proceed to the next Test Step.

8. Oil Pump Suction Tube

   1. Remove the oil pan.

   2. Inspect the suction tube. Check the joints of the tube for cracks or for a damaged O-ring seal at the connection to the pump.

   3. Inspect the inlet screen of the suction tube for a restriction. This restriction will cause cavitation and a loss of engine oil pressure.

   4. Replace parts, if necessary.

   5. If the symptom is corrected, return the unit to service.

   6. If the symptom remains, proceed to the next Test Step.

9. Worn Engine Components

   1. Remove the valve covers.

   2. Inspect the camshaft and bearings.

   3. Remove the oil pan.

   4. Excessive clearance at the crankshaft or camshaft bearings will cause low engine oil pressure. Check the engine components for excessive clearance. Also, inspect the piston cooling jets.

   5. Replace parts, if necessary. Check the Reuse and Salvage Guidelines for the reusability of existing engine components.