ISM, ISMe, and QSM11 – Crankcase Coalescing Filter – Frequent Replacement

Symptom Tree  t028

This is symptom tree t028
Cause Correction

Filter miles or hours is at expected maintenance interval for replacement.

Review the engine’s maintenance records to determine if the crankcase breather filter replacement is at expected interval or not based on crankcase blowby. Replace filter if acceptable.


Lubricating oil level is above specification

Check the oil level. Verify the dipstick calibration and oil pan capacity. Fill the system to the specified level. Refer to Procedure 007-009.


Crankcase ventilation system is plugged

Check and clean the crankcase breather and vent tube. Refer to Procedure 003-002.


Lubricating oil is contaminated.

Analyze oil sample for fuel dilution percentage, coolant in oil, and foreign contamination. Repair the source of contamination.


Engine Crankcase Gases (Blowby) excessive.

Refer to Crankcase Gases (Blowby) Excessive Troubleshooting Symptom Tree.

Last Modified:  14-Aug-2006