Topic number – GI09.40-P-063893
Date – 05-03-2017
Validity
Engine OM651 in model 166, 172, 205, 222, 253
Engine OM651 in model 204, 207, 212, 218 (with code B03)
Complaint
Rattling noise from front of engine on right, in area of turbocharger.
The complaint predominantly occurs for a short time after a cold start.
Soundfile – File hosted by www.w212ownersforum.com
Cause
Various causes are possible:
1. Belt tensioner.
2. Vibrations of the aluminum bypass valve inside the air duct housing.
Remedy
The following diagnostic steps must be performed in sequence:
1. Remove poly-V belt (see AR 13.20-P-0001)
2. Run the engine at idle for max. 60 seconds after a cold start
3. Reproduce the problem noise
Does the noise remain unchanged?
NO:
– The belt drive is where the problem occurs. The belt tensioner probably causes the noise.
– The air duct housing must NOT be replaced.
YES:
Remove the air duct housing.
– If a silver-colored aluminum valve (Pic 1) is installed, replace the air duct housing.
– If a black plastic valve (Pic 2) is installed, the air duct housing must NOT be replaced.
Note: The noise behavior of the air duct housing and the bypass valve is altered by removal.
Therefore any noise analysis in the removed state (e.g. by shaking the housing or the valve) is irrelevant.
Note: The part number of the air duct housing was not changed when converting from the aluminum to the plastic valve.
Pic1
Pic2
Parts
A 651 090 18 07 Turbocharger air duct housing 1 Model series 205 / 253 & model series 172 with code A09 X
A 651 090 17 07 Turbocharger air duct housing 1 Model series 166 X
A 651 090 15 07 Turbocharger air duct housing 1 Model series 212 hybrid / 222 & model series 172 without code A09 X
A 651 090 14 07 Turbocharger air duct housing 1 Model series 204 / 207 / 212 / 218 with code B03 X