GM Service Manual Online
For 1990-2009 cars only

Cause

Correction

Incorrect oil filter without anti-drainback feature

Install the correct oil filter.

Incorrect oil viscosity

  1. Drain the oil.
  2. Install the correct viscosity oil.

High valve lifter leak down rate

Replace the lifters, as required.

Worn crankshaft thrust bearing

  1. Check the crankshaft end play.
  2. Inspect the thrust bearing and crankshaft.
  3. Repair or replace, as required.

Damaged or faulty oil filter bypass valve

  1. Inspect the oil filter bypass valve for proper operation.
  2. Repair or replace, as required.