Turbocharger General Inspection

DIAGNOSTIC AIDS:
The turbocharger is not serviceable and must be replaced as a unit. Most turbocharger failures are caused by lack of lubrication, contaminated oil, or foreign object damage to the compressor blades or the turbine blades. It is important to determine the exact cause of a turbocharger failure before a replacement unit is installed. A visual inspection should be performed initially.


A turbocharger has its own distinctive sound, or noise level, when operating. In many cases, malfunctions can be identified by either a low pitched sound or a high pitched sound. If the sound of the turbo cycles up and down in pitch, check for an inlet air restriction or heavy dirt build up in the compressor housing and on the compressor wheel. If the noise level is a high pitch or whistling, look for an inlet air or exhaust gas leak.

With the engine shut OFF and the turbo stopped turning completely, make a visual inspection of the turbocharger and components.



WARNING: Operation of the turbocharger without all ducts and filters installed can result in personal injury, or foreign objects damaging the wheel blades.


INSPECTION
1. Check for loose duct connections from the air cleaner to the turbo.
2. Check the cross-over duct from the turbocharger to the engine intake system. A loose duct can cause low power, and noise.
3. Check the wheels of the turbo for impact damage from foreign objects, entering from engine or ducting.
4. Check for evidence of wheel contact against the housing walls.
5. Check the shaft for free rotation. Stiffness could indicate the presence of sludged oil, or coking from over-heating. Push inward lightly in one of the shaft wheels while you turn it by hand and feel for any rubbing or binding. Do the same in the other side. The wheels should turn freely without contact housing, backplate or shroud.
6. Check the exhaust manifold for loose connections and cracks.
7. Check the oil drain line for restriction. Any restriction can cause severe oil loss through the turbo seals. There may also be traces of burned oil on the turbine housing exterior.
8. Check the oil supply line to ensure it is clean and unobstructed. Restricted oil flow can result in severe damage to the turbocharger.