SCREW 3F2734 - Caterpillar

Procedure
Install an in-line check valve into the inlet hose of the air compressor. Proceed to Step 2 and Step 3, if installing the check valve does not resolve the issue.
Use the 261-0940 Test Kit if the air compressor is still passing excess engine oil. This test kit contains the information and the tooling that is necessary for this process. The process uses a calibrated measuring cup to drain the fluids from all of the air tanks. The kit determines the amount of oil that is allowed to crossover into the air tank. The test results, and other information are recorded on a data sheet that is included in the kit.
Replace the compressor if the test results are out of the acceptable range.Refer to Table 1 in order to find the correct air compressor that is used on the affected engines.
Table 1
Engine Model     Part Number     Description    
C7 or C9     10R-9391     Air Compressor Gp    
C13     10R-9392     Air Compressor Gp    
C15     10R-9393     Air Compressor Gp