Mercedes-Benz OM 904-926 LA BlueTec Operating Instructions Manual page 95

Problem
Engine emits black
smoke.
Exhaust fumes are
blue.
Exhaust fumes are
white.
Engine "knocks".
Knocking noise from
the bearings.
There are abnormal
sounds.
Possible causes/consequences and M Solutions
Poly-V-belt is torn.
X
Replace poly-V-belt (
Alternator or sensor is defective.
X
Check alternator or sensor.
X
Consult a qualified specialist workshop.
Air filter is very dirty.
X
Replace the air filter element.
Engine brake is faulty.
X
Consult a qualified specialist workshop.
Exhaust gas turbocharger is faulty.
X
Carry out a visual check.
X
Consult a qualified specialist workshop.
Misfiring, fuel injector is faulty.
X
Consult a qualified specialist workshop.
The oil level in the engine is too high; the crankcase ventilation
system is faulty; engine oil has entered the combustion chamber.
X
Adjust the oil level correctly.
X
Have the crankcase ventilation system checked at a qualified
specialist workshop.
Coolant is entering the combustion chamber.
X
Have a pressure loss test carried out at a qualified specialist
workshop.
The engine is misfiring.
X
Consult a qualified specialist workshop.
There is bearing damage.
X
Consult a qualified specialist workshop.
Leaks in intake pipe and exhaust pipe cause whistling noise.
X
Repair leaks; replace seals if necessary.
Troubleshooting
Y
page 97).
93
Z