C7 and C9 Industrial Engines Troubleshooting – Oil Pressure Is Low

Probable Causes

 

  • Engine oil level 
  • Engine oil filters and oil filter bypass valve 
  • Engine oil pump 
  • Engine oil cooler 
  • Fuel dilution 
  • Engine wear 

Recommended Actions

Table 1
Troubleshooting Test Steps Values Results
1. Engine Oil Level

A. Inspect the engine oil level.

Level Result: The oil level is correct.

Proceed to Test Step 2.

Result: The oil level is not correct.

Repair: If engine oil is low, add engine oil. Refer to the Operation and Maintenance Manual.

2. Engine Oil filters and Oil Filter Bypass Valve

A. Check the service records of the engine for information that is related to the last oil change.

B. Check the operation of the oil filter bypass valve.

Oil Filter Result: The engine is up to date with service and the operation of the oil filter bypass valve is working correctly.

Proceed to Test Step 3.

Result: The engine is not up to date with service and the oil filter bypass valve is not properly operating.

Result: Perform an oil change on the engine with new filters and clean the bypass valve and the housing. If necessary, install new parts.

3. Engine Oil Pump

A. Check for blockage of the inlet screen for the engine oil pump.

B. Check the components of the engine oil pump for excessive wear.

Oil Pump Result: There is no blockage of the inlet screen and the engine oil pump components do not have excessive wear.

Proceed to Test Step 4.

Result: There is blockage of the inlet screen and/or the engine oil pump components have excessive wear.

Repair: Remove blockage from the inlet screen and repair the oil pump or replace the oil pump.

4. Oil Cooler

A. Check the inlet side of the oil cooler for debris or blockage.

Restriction Result: There is no debris or restrictions in the oil cooler.

Proceed to Test Step 5.

Result: There is debris or restrictions in the oil cooler.

Repair: Clean or replace the oil cooler.

If the problem is not resolved, proceed to Test Step 5.

5. Fuel Dilution

A. Check for presence of fuel in the lubricating oil.

Refer to the troubleshooting without a diagnostic code procedure Troubleshooting, “Fuel Dilution of Engine Oil”.

Fuel Dilution Result: There is no presence of fuel in the oil.

Proceed to Test Step 6.

Result: There is presence of fuel in the oil.

Repair: Make the necessary repairs and return to service.

6. Engine Wear

A. Inspect the camshaft and/or camshaft bearings for excessive wear.

B. Inspect the crankshaft and/or crankshaft bearings.

Excessive wear to discrete components may be an indication of a blocked oil passage. Use an oil pressure gauge to check the oil pressure at the main oil gallery. This will help determine if the excessive wear is from low system pressure or from passages that are blocked.

Engine Wear Result: There is excessive wear on the camshaft, camshaft bearings, and/or crankshaft, crankshaft bearings.

Repair: Repair or replace the damaged components and return to service.

 

Posted in C7

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