2011 E350 CDI engine rattle, alloy bits in engine

Page may contain affiliate links. Please see terms for details.


New Member
Aug 25, 2023
E350 CDI Convertible
Hi everyone

I have just joined the forum, I have had a 2011 E350 CDI convertible for about 10 months and its been running well. Recently I arrived home and got out the car and noticed a sort of slapping ticking noise coming from the engine. I had driven about 30 or so miles and the engine was fine when I set out, the car was also running well and completely as normal as far as I could tell driving it. The only sign of any issues was the noise, I let the car cool overnight and gave it a cold start and the noise had almost gone but returned quite quickly. I took it right up to my local garage a mile away and the verdict was it does not sound like ancillary stuff and that the noise was most likely internal.

I booked the car in and 2 weeks later it was in the garage being looked at. The mechanic called me initially and said the only thing he could see at that stage was that the timing chain was a bit slack and that he would have to strip it further but suspected a broken chain guide. A few days later he called and said that he could not see anything at the front of the engine but that he had found a couple of bits of aluminium in the engine. He rang his engine specialist and was told that these engines suffer from main bearing failure and it could be that. In his opinion it would be best not to attempt a repair but to source a replacement engine. A search around the web later I see that engines vary from around £3000-4000 which isn't exactly in my budget at the moment along with the labour.

The mechanic said of course you can do a lot of repairs for a couple of grand so I'm a bit torn as to what to do, a used engine with around 100,000 miles could of course develop a fault. So is it best to chance another engine or spend maybe a bit less and risk a repair on my engine, any thoughts would be greatly appreciated. I was about to sell the car anyway so its a huge pain as I have been looking at C63 AMG convertibles. I had a 2007 CL63 AMG with the glorious M156 6.2 engine but it was sadly written off recently and I am missing the noise! I need a V8 in my life again :)
OM642 is known 'stretching' the timing chain, but usually that cause no big problems, and cold noise is just indicator. Tensioner condition can be checked via oil filler hole in older engines, latter no when they moved filler bit backward.

Also it is known (quite rare) fact that exhaust manifold (two layer structure) inners will brittle and bits are usually ruining the turbo.
Is this an MB specialist?
If not a Merc specialist who works on these all day long with a long experience of OM642 repairs and failures, I'd pay the £200 or whatever it is to get it trailered to a good independent specialist.

Were there any fault codes with STAR?
Has the oil been drained or sump dropped to check for metal damage/debris as best as possible?
Last edited:
Hi everyone

he had found a couple of bits of aluminium in the engine.
That's the clue right there. Where they came from (and where they were found) is where the problem resides.
Was looking at a OE 642 852 engine yesterday in search of an OE 642 862 for a 2012 W221 which has seized, would be good to know the outcome of this thread.
He rang his engine specialist and was told that these engines suffer from main bearing failure and it could be that.
If this is an OM642 engine, I've never heard of any instance of main-bearing failure.
If it is main bearing failure, I can't see the bits being aluminium.
Anyone else see it as I do ?

Users who are viewing this thread

Top Bottom