Important: If the turbocharger does not pass any one of the inspections that indicate damage to the turbocharger, with the exception of the waste-gate actuator, replace the turbocharger. Refer to Inspection of the Waste-Gate Actuator.

Turbochargers are extremely reliable units. The majority of inoperative turbochargers are caused by the following problems.

Lack of power, black smoke, blue smoke (excess oil consumption), or other engine performance problems are frequently blamed on the turbocharger. The actual cause is usually from another engine component. This is why a complete inspection of the turbocharger should be performed. All other engine components that may cause similar conditions must be examined before replacing the turbocharger. If it is determined that the turbocharger is the cause of the problem, the turbocharger must be replaced. Service of the turbocharger is not recommended.

The following steps will help in diagnosing problems caused by the turbocharger.

1. Inspect the turbocharger if a high-pitched whine is heard. This may indicate an exhaust leak or a leak in the air induction system.
2. Inspect the turbocharger if there is a cycling up and down in pitch. This often indicates a blockage in the air inlet duct, a restricted air cleaner, or a build-up of dirt on the compressor wheel of the turbocharger.
3. Examine the bearings for deterioration if a sharp, high-pitched scream is heard. This may also be the cause of one (or both) of the wheels rubbing on its housing.
4. Inspect the compressor wheel blades. There should not be any bent, broken, eroded, or cracked wheel blades.
5. Examine the housing for signs of rubbing.
6. Inspect the compressor wheel for a build-up of dirt.
7. Check for oil leaking into the turbocharger housing.

Important: Due to the venting of crankcase vapors into the air intake system, the inside of the air intake duct, the turbocharger compressor wheel and the housing can become quite oily. This is considered normal.

8. There are several problems that can cause excess oil to leak into the turbocharger housing.

-	Too much idling of the engine

-	Obstructed air intake duct or a clogged air filter

-	Plugged or kinked oil drain tube from the turbocharger

-	Sludged oil accumulations in the center housing

-	Damage to the turbocharger bearings or wheels

Caution:  Avoid contact with moving parts and hot surfaces while working around a running engine in order to prevent physical injury.

9. Using your fingers, carefully grasp the compressor wheel nut and rotate the wheel to the left.

The wheel should turn freely. There should be no signs of binding or scraping.

10. Inspect how the turbocharger rotates while pushing in and pulling out on the compressor wheel.

The turbocharger should rotate freely and have no contact with the housing.

11. Carefully grasp the compressor wheel nut with your fingers. While rotating, move the wheel up and down (radially).

There should be no compressor wheel-to-housing contact. Axial and radial play is normal, even on a new turbocharger. The existence of compressor wheel-to-housing contact will be evident when rotating the wheel. The wheel will drag or scrape on the housing surface. Visual damage should be evident on the wheel blades and the housing surface.