C7 and C9 Industrial Engines Troubleshooting – Oil Consumption Is Excessive

Probable Causes


  • Oil leaks 
  • Oil level 
  • Turbocharger seal 
  • Internal engine wear 

Recommended Actions

Table 1
Troubleshooting Test Steps Values Results
1. Oil Leaks

A. Check the engine compartment for any oil leaks.

Oil Leaks Result: There are no oil leaks in the engine compartment.

Proceed to Test Step 2.

Result: There are oil leaks in the engine compartment.

Repair: Find the source of the oil leaks and perform the necessary repairs.
Verify that the repair eliminated the problem.

2. Oil Level

A. Check the engine oil level. Too much oil in the engine crankcase can cause the engine to consume oil.

B. Ensure that the dipstick is properly calibrated correctly for the installation.

Oil Level Result: The oil level is correct and the dipstick is correctly calibrated.

Proceed to Test Step 3.

Result: The oil level is high or the dipstick is incorrectly calibrated.

Repair: Remove excessive engine oil from the crankcase.

3. Turbocharger

A. Check the turbocharger shaft seal for leakage.

B. Remove the air inlet piping and the exhaust outlet piping from the turbocharger.

C. Check the compressor wheel and the turbine for evidence of an oil leak.

Turbocharger Result: The turbocharger shows no sign of any leaks.

Proceed to Test Step 4.

Result: The turbocharger shows signs of an oil leak.

Repair: Repair the turbocharger or replace the turbocharger. Refer to Systems Operation and Testing and Adjusting.

4. Internal Engine Wear

A. Check for excessive crankcase blowby at the engine crankcase breather.

Internal engine wear can cause excessive oil leakage into the combustion area of the cylinders. Excessive wear on the following components may cause oil consumption:

 Piston Rings

 Valve Guides

Engine Wear Result: There is not excessive blowby at the crankcase breather.


Result: There is excessive blowby at the crankcase breather.

Repair: Repair or replace the worn or damaged parts. Verify that the repair eliminated the problem.


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