Vibration at low revs

[goodoldfred]

Over the last few months my 10 year old SL350 R231 has developed an annoying vibration when the car is being driven very slowly or paused at junctions etc. The indeepndent Mercedes servicing garage I use has checked it out and confirmed no body parts are touching and all supports are OK. It seems to be associated with the tickover speed which is 600 rpm. Above that it seems to be fine. Apparently however tickover is set by the ECU so can't be adjusted. It's a low mileage car and I've only ever used Shell VPower. I would appreciate any suggestions.

 

[axelcls]

When your gearbox was serviced last time ?


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[malcolm E53 AMG]

I assume this is the M276 engine what mileage has it done?

 

[alexanderfoti]

Engine and or gearbox mounts are the most likely culprit

 

[ajlsl600]

As above.

 

[brandwooddixon]

I'd agree with @alexanderfoti , especially if its worse when stationary and in drive than when stationary and in neutral.

 

[peterws1957]

Over the last few months my 10 year old SL350 R231 has developed an annoying vibration when the car is being driven very slowly or paused at junctions etc. The indeepndent Mercedes servicing garage I use has checked it out and confirmed no body parts are touching and all supports are OK. It seems to be associated with the tickover speed which is 600 rpm. Above that it seems to be fine. Apparently however tickover is set by the ECU so can't be adjusted. It's a low mileage car and I've only ever used Shell VPower. I would appreciate any suggestions.

Which indie did the inspection. I would have thought that the motor and gearbox mounts would have been one of the first things to check.

 

[goodoldfred]

When your gearbox was serviced last time ?


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Not sure but that's someting to look into.

When your gearbox was serviced last time ?


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It's something I'm going to look into.

 

[goodoldfred]

Which indie did the inspection. I would have thought that the motor and gearbox mounts would have been one of the first things to check.

I'm going to get another one to check them out.

 

[goodoldfred]

I assume this is the M276 engine what mileage has it done?

Very low - only 32,000.

 

[malcolm E53 AMG]

There is a lot of useful information on the net - put a search in for problems with the M276 engine and have a read:

4 Common Mercedes M276 Engine Problems

Learn about Mercedes M276 engine problems including the HPFP, carbon build-up, and timing chain tensioner. Is the M276 reliable?

tuningpro.co

My guess would be carbon build-up DI engines do suffer with this certainly needs checking out

 

[nom de plume]

Just bought an R231 V6 SL350 with M276 engine. Less than 16k on the clock but vibration through the steering wheel and body when engine warm and drops to 600 revs is more than I would expect. Also bit of an underbody clunking sound when auto restart kicks in. My reliable Indie checked out the exhaust system and found all as it should be. There was a blog saying that replacing the rear transmission mount fixed theirs, so I bought the 50 quid mount but it made zilch difference. On this topic I've seen mentions of carbon build up (and given the mileage, mine must have had a lot of short distance trips) due to the location of the fuel injectors in this engine, also PCV (crankcase breather valve) failure allowing slight pressure build-up. Other maybe weird ones are DaimlerAG LI54.18-P-058597 report on 'engine lamp inactive' and fault codes P213500, P213629 and P213700 related to throttle valve actuator (but all that stuff is far too tech for me to understand!). ANYBODY MANAGED TO MAKE ANY PROGRESS ON THIS TOPIC PLEASE? Same engine fitted in 2013 era of W221 S350, W218 CLS350, W212 E350, W166 ML350, R172 SLK 350 and W204 C350.