Turbocharger, Trouble Shooting - Man D 2842 LE 620 Repair Manual

Table of Contents

Before removing the turbocharger carry out the following checks

Turbochargers are frequently exchanged if the oil consumption is too high, the output too low or the intake

and / or exhaust gas noises appear to be abnormal.

Subsequent inspections by the manufacturer of the supposedly defective parts frequently prove the turbo-

chargers to be in order.

To ensure that only defective turbochargers will be exchanged in future, the following checks are to be car-

ried out beforehand:

If the oil consumption is too high

− Check air filter for contamination

− ensure that the engine room ventilation is adequate

− check intake pipe for cross section reduction (owing e.g. to damage, contamination)

These causes lead to higher oil consumption owing to the increased vacuum on the intake side of the com-

pressor.

− Check outside of turbocharger for oil traces

Oil consumption caused directly by turbocharger depends on the bearing wear and results in relatively early

mechanical damage.

If engine performance is not satisfactory

Correct adjustment of the

− delivery start

− valve clearance

− speed adjustment (to full load stop)

In addition, the following are to be checked:

− the compression

− the air filters for contamination

− the charge-air pressure

− intake system for reduction of cross-section and for leaks

− exhaust system for damage and leaks

If you do not detect any possible cause in the above checks, check the turbocharger for:

− Carbonization in the turbine area, which impairs the movement of the wheel assembly

(can be eliminated by axial movement)

− Dirt in the compressor area

− Damage caused by foreign objects

− Scraping of the turbine rotor on the housing

If a considerable amount of dirt has accumulated, clean the compressor end and check the bearing

clearance.

Caution:

Do not damage the aluminium compressor wheel.

When there is unusual intake or exhaust noise

− Check the intake and exhaust system in the area of the charger group.

Defective gaskets can lead you to think the turbocharger is defective. Replace them.

− If there are still unusual noises, check the bearing clearance.

Turbochargers in good working order do not make any excessive noise.