Engine - Oil Leak in Extreme Cold Conditions
TSB SB05-01-S005Oil Leak Under Extreme Cold Temperatures
ISSUE DATE: JULY 2005
Affected Vehicles
2003-2005 Isuzu Ascender (US) with 5.3L Engine
Service Information
Condition:
Some customers may comment on an engine oil leak under extreme cold temperatures (-34°C (-30°F) or colder). The customer may also comment that there may be some oil seepage out of the engine oil level indicator (dipstick) and/or out of the front or rear crankshaft seals during engine operation only.
Possible Cause:
Under extremely cold temperatures (-34°C (-30°F) or colder) and extended driving conditions, the PCV system may experience a freezing condition and keep crankcase gases from passing through the PCV system. This may cause crankcase pressure to rise steadily and, in some cases, this high pressure pushes out the oil level indicator from the tube and causes an oil leak during engine operation.
IMPORTANT:
If a visual inspection indicates that oil is still leaking from the front or rear crankshaft seals after this bulletin has been performed, then further diagnosis must be performed using the Oil Leak Diagnosis and/or Crankcase Ventilation System Inspection/Diagnosis in the Service MManual.
Correction:
Follow the service procedure below for diagnosis and correction of this condition.
Service Procedure
1. Inspect the oil fill dipstick to see if it has been pushed out of the tube and if there is engine oil seeping out of the engine under operation. This condition could be causing the PCV valve to freeze shut.
2. If an icing or freezing condition is found with the PCV valve inspection, then replace the oil fill cap with a vented oil fill cap.
3. Use a new vented oil fill cap, P/N 8-12589-430-0. A vented oil fill cap will regulate the crankcase pressure between 15 kPa and 18 kPa.
This will prevent over pressurization of the crankcase under the freezing conditions of the PCV system. Once the PCV system thaws out, the crankcase gases will pass through the PCV system and normal crankcase pressure will be restored.
4. Inspect the engine oil level. Start and operate the engine under normal conditions and visually inspect that the engine oil leak has been repaired. If another engine oil leak has been detected, then refer to the Service Manual for further assistance in repairing the condition.
Parts Information
Warranty Claim Information
Use the labor operation table.
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