Initial Inspection and Diagnostic Overview

Inspection









Turbochargers are extremely reliable units. The majority of inoperative turbochargers are caused by dirt in the oil, oil lag (lack of oil flow), foreign objects or debris entering the turbocharger, and plugged or restricted air cleaner systems.

Lack of power, black smoke, blue smoke (excess oil consumption), or other engine performance problems are frequently blamed on the turbocharger when the actual cause is really another engine component. This is why a complete inspection of the turbocharger and all other engine components that may cause similar conditions must be examined before replacing the turbocharger. The following steps and the preceding diagnostic chart will aid in diagnosing problems caused by the turbocharger. If it is determined that the turbocharger is the cause of the problem it must be replaced. Service of the turbocharger is not recommended.

Inspect















^ A high pitched whine may indicate an exhaust leak or a leak in the air induction system.
^ A cycling up and down in pitch 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.
^ A sharp, high pitched scream may indicate that the bearings have deteriorated and one (or both) of the wheels is rubbing on its housing.
^ At the compressor wheel blades. There should not be any bent, broken, eroded, or cracked wheel blades.
^ At the housing for signs of rubbing.
^ At the compressor wheel for a build-up of dirt.
^ For oil leaks into the turbocharger housing.

Important

^ With this engine application, the inside of the air intake duct (rubber inlet elbow), turbocharger compressor wheel and housing can be quite oily, due to the venting of the crankcase vapors into the air intake system. This is considered normal.

Some of the problems that can cause oil leaks in excess into the turbocharger housing are:

A. Too much idling of the engine.
B. Obstructed air intake ducting or clogged air filter.
C. Plugged or kinked oil drain tube from the turbocharger.
D. Sludged oil accumulations in the center housing.
E. Damage to turbocharger bearings or wheels.

CAUTION: Do not feel any components of the turbocharger while the engine is running. Make sure that the turbocharger has stopped rotating and the turbocharger and engine have cooled down before handling. Rotating parts and extreme heat may cause serious personal injury if handled.

^ Carefully grasp the compressor wheel nut with fingers and rotate the wheel in a clockwise direction. It should turn freely with no signs of binding or scraping (housing contact).

^ How the turbocharger rotates while pushing in and pulling out on the compressor wheel; it should rotate freely with no contact with the housing.

^ Carefully grasp the compressor wheel nut with fingers and while rotating move the wheel up and down (radially). There should be no compressor wheel to housing contact. Note: axial and radial play is normal even on a new turbocharger. If compressor wheel to housing contact exists, it will be very evident when rotating the wheel. The wheel will drag or scrape on the housing surface and visual damage will probably be evident on the wheel blades and housing surface.

Important

If the turbocharger does not pass any one of the above inspections that indicate damage to the turbocharger, with the exception of the waste-gate actuator, then the turbocharger must be replaced.