Petrol sounding like a diesel..

[jimbob35]

When starting from cold the engine spends the first second or two clattering like a diesel, there is also a momentary metal grating noise and then all is well..

The oil has recently been topped up, but this has been occurring pre/post last service a few months ago. I neglected to mention it at the service.

It does sometimes happen when starting a warm engine, but less noticeable.

Any ideas fellas?

 

[markjay]

Clattery noise when cold is usually associated with valve gear, in which case a dose of Wynns may sometimes help.
http://www.halfords.com/webapp/wcs/..._productId_203145_langId_-1_categoryId_165750

Timing chain rattle should not go away when car is worm AFAIK.

But a one-off grinding noise - could it be that the starter motor does not disengage properly?

 

[Two 202s]

Hi, what milage are you at and has it been serviced regularly?
Could it be two seperate issues like initial cam rattle oil starvation and also a worn alternator bearing?

 

[rhud]

'Petrol sounding like a diesel' is exactly how I would describe a clatter which is occurring in the engine bay of my 2010 A Class at present,awaiting dealer investigation. It's when the engine is idling - or at least that's when it's most apparent.

Someone with more knowledge than me said it sounded like 'a belt noise' - maybe 'alternator pulley'. Will report further in due course.

 

[Sp!ke]

Likely culprit is the belt tensioner damper.

 

[jimbob35]

Thanks for the responses. I'll give the Wynns a try for sure.

The alternator is new, and the noise occurred before and after it was replaced so I think I can rule that out.

I'm close to 80k, full Mercedes service history. B service due in 3k miles.

The belt tensioner dampener 'feels' like something I could check myself, would that be possible?

Thanks

 

[HF2]

I had someting similar on my W202 @ about 120k.


To fix it I used engine flush, follow the instructions on the tin, then drain the old oil (notice the sludge and crap) then change oil filter and fill with new good quality oil.