WASHER 5D5205 - Caterpillar

The crankcase breather includes a pressure relief valve that prevents a build-up of excessive pressure in the breather system.
Illustration 1 g02919637
(1) Crankcase pressure relief valve In normal operation of the engine, the pressure relief valve remains closed. If there is evidence of oil staining around pressure relief valve (1), perform the following procedure in order to diagnose the fault.Probable Causes
Breather filter
Breather hoses
Breather heater
Excessive blow-byRecommended Actions
Illustration 2 g02919737
Table 1
Troubleshooting Test Steps Values Results
1. Breather Filter
A. Check that the breather element is correctly installed and that the element is not damaged.
B. Check for restrictions or blockages in orifice (2).
Breather filter
Result: The breather element is incorrectly installed or damaged.
Repair: Install a new filter element. Refer to Operation and Maintenance Manual, "Engine Crankcase Breather Element - Replace".
Note: If a new filter element blocks before the service period is completed, the blockage can indicate a fault in the engine.
Result: There is a restriction or blockage in orifice (2).
Repair: If necessary, replace the crankcase breather. Refer to Disassembly and Assembly, "Crankcase Breather - Remove" and refer to Disassembly and Assembly, "Crankcase Breather - Install"
Result: The breather filter is OK.
Proceed to Test Step 2.
2. Breather Hoses
A. Check the oil return hose and the breather outlet hose for restrictions or blockages.
Breather hoses
Result: There is a restriction or blockage in one of the breather hoses.
Repair: Replace the breather hoses, as necessary.
Result: The breather hoses are OK.
Proceed to Test Step 3.
3. Breather Heater
A. Turn the keyswitch to the OFF position.
B. Disconnect the breather heater connector.
C. Turn the keyswitch to the ON position.
D. Use a suitable multimeter to measure the voltage at the harness connector for the heater.
E. Turn the keyswitch to the OFF position.
F. Use a suitable multimeter to measure the resistance of the heater element.
10 V to 14 V for step D
Less than 10 k Ohms for step F.
Result: The measured voltage is less than 10 V.
There is a fault in the wiring to the breather heater.
Repair: Repair the harness or repair the harness
Result: The measured resistance is greater than 10 k Ohms.
Repair: Replace the breather heater.
Result: All measurements are within the expected ranges.
Proceed to Test Step 4.
4. Excessive Blow-by
Excessive blow-by increases the flow of fumes through the breather system and can cause the breather element to block. The pressure relief valve may then open.
A. If excessive blow-by is suspected, replace the breather element. Refer to the Operation and Maintenance Manual, "Engine Crankcase Breather Element - Replace".
B. Investigate the cause of the excessive blow-by. Refer to Troubleshooting, "Oil Consumption Is Excessive".
Blow-by
Result: The fault has been rectified.
Return the engine to service.
Result: The fault is still present.
Contact the Dealer Solution Network (DSN).