Man D 2866 LUE 602, Repair Manual

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Turbocharger, troubleshooting
79
Before replacing the turbocharger, perform the following checks
It is frequently the case that with excessive engine oil consumption, low power or abnormal intake and/or
exhaust noise the turbocharger is replaced.
When the allegedly defective part is then checked by the manufacturer, it is often determined that the char-
ger is OK.
To ensure in the future that only defective turbochargers are replaced, the following checks must be carried
out first:
In the case of excessive oil consumption
- Check the air filter for soiling
- Check whether the diameter of the intake line has been reduced (e.g. due to damage, soiling).
All of these cause higher oil consumption due to the increased vacuum.
- Check the outside of the turbocharger for traces of oil.
Oil consumption caused directly by the charger depends on the bearing wear and leads relatively quickly to
mechanical damage.
In the case of unsatisfactory engine power
A requirement for a satisfactory level of engine power is setting in accordance with regulations
start of fuel delivery
- and of the valve clearance
- speed adjustment (pedal value)
The following must also be checked
- the compression pressure
- soiling of the air filters
- the intake system for reductions in diameter and leaks
- the exhaust system for damage and leaks
If these checks do not lead to detection of a possible cause, the turbocharger must be checked for
- coking in the turbine area leading to sluggishness of the rotor assembly
(can be remedied by axial movement)
- coarse dirt in the compressor area
- damage caused by foreign bodies
- scraping of the rotor disk on the casing.
In the case of coarse dirt, the compressor side must be cleaned and the bearing clearance checked.
Caution:
Do not damage the light-alloy compressor wheel.
In the case of abnormal intake and exhaust noise
- Check the intake and exhaust system in the area of the charge group.
Damaged gaskets lead to false diagnosis of a defective turbocharger; these must be replaced.
- If the abnormal noise is still present, replace the turbocharger.
Mechanically perfect turbochargers do not generate any noise!