GM Service Manual Online
For 1990-2009 cars only

Condition

Action

Some whine noise is normal. Compare to a known good vehicle.

Leaking charge air cooler/pipes/hoses

Inspect for leaks in charge air cooler/pipes/hoses using J 46091 .

Worn turbocharger bearings

Visually inspect for evidence of compressor wheel to housing contact.

If the turbocharger bearings are worn or damaged, inspect for a Turbocharger Lack of Oil Supply.

Intake system leaks or obstructions

  1. With the engine off, pressurize the intake system using J 46091 and inspect for intake manifold leaks.
  2. Inspect for obstructions in the intake manifolds.