The crankcase vent filter cartridge includes a pressure relief valve to prevent excessive pressure buildup.
Under normal engine operation, the pressure relief valve remains closed. If there is oil residue on the cylinder head behind the vent filter cartridge, perform the following steps to diagnose the problem.
Possible Causes
• Breather Filter
• Vent Hose
• Excessive Blow-In
Recommended Actions
Caterpillar ET 2026A & 2019C Electronic Technician Diagnostic Software Download and Installation
Typical Vent Filter Cartridge
(1) Breather Filter Canister Cap
(2) Filter Element
(3) Vent Filter Cartridge
Note: These steps are listed below in order of probability. Perform these steps in sequence.
Troubleshooting and Troubleshooting Test Steps
CAT Comm Adapter3 478-0235 Diagnostics for Caterpillar
1. Vent Filter
A. Check the filter element
(2) for proper installation and for any damage. B. Check the breather filter canister (3) for any obstructions or blockages.
Note: In cold weather, the outlet of the respirator filter canister may freeze.
Result: Filter element (2) is improperly installed or damaged.
Repair: Correctly install or replace the filter element.
Result: Respirator filter canister is clogged or blocked.
Repair: Clean the inside of the respirator filter canister.
Result: The respirator is clean and functioning properly.
2. Vent Hose
A. Ensure the return hose of the vent filter cartridge is not squeezed or blocked.
B. Ensure the vent outlet hose of the vent filter cartridge is not squeezed or blocked.
Result:
One or more hoses are squeezed or blocked.
Repair: Clean or replace the hose.
Result: All hoses are clear. Proceed to test step 3.
3. Excessive Blow-In
Note: Excessive blow-in increases the amount of smoke flowing through the respirator system, leading to filter clogging. The pressure relief valve may subsequently open.
A. Check the engine for excessive blow-by.
Result: Excessive blow-by.
Repair: Replace the breather filter.
Investigate the cause of the excessive blow-by. Please refer to Troubleshooting and Repair, "Excessive Oil Consumption".
Result: Blow-by is not excessive.
Please contact the Dealer Solutions Network (DSN).
