M112 Timing Chain Noise.

[@the8419]

Nothing to worry about. Many of them do that and last 250,000-300,000+ miles. They are noisy engines to begin with.

[@lobmati5998]

Can you speak from experience? Have the same rattling against the cover but in longer spaces between the intervals and quieter(so not as severe?) thought about just pulling trough a new chain and changing the chain tensioner when I’ll clean the valve cover sometime this year

[@leddjon1166]

@@lobmati5998 its timing chain. I wouldn't be driving with this noise. You should replace the timing chain and the guides - which is difficult to do without taking off the heads but mine car mechanic did this. You need to cut the pines which holds the guides and put these with glue. I bought my mercedes with this sound, i knew that is timing chain, now all i can hear is beauty of v6 :)

[@makarsopcee3285]

I did 50k km on loose timing chain

[@leddjon1166]

@@makarsopcee3285 would you bet all of your money that he will do the same ?:p

[@charlesphiliparthurgeorgep4653]

@@lobmati5998 Yes, I can. Owners have reported putting 200,000+ miles on their M112/M113 engines after they notice the sound. It generally doesn’t get any worse than this. I also know a few Mercedes Master technicians, and they’ve NEVER seen chain failures on these engines... and say it’s nothing to be scared of. Even if it got bad enough to be a problem, you’d get timing codes well before anything catastrophic occurs. Pulling in a new chain is fairly easy, and will may give you peace of mind... but not necessary.

[@mrkring1526]

Definitely timing chain. I have the same sound on my E320. I dont think it will ever snap just how they sound after a while

[@Markus-qo6zk]

Error Code P203D camshaft what is this?

[@reki353]

uhhhh those are the secondary air diverter valves, not anything to do with the the valvetrain

[@neps4th]

What?

[@reki353]

@@neps4th the two gold looking things, the sound is coming from those, if you put your ear near it you will hear it.

[@richardcase6933]

Had the same sound on my ml 320 went away when i replaced water pump

[@stardock3859]

It was exactly the same noise ?

[@richardcase6933]

@stardock3859 yes

[@Slowwvqs]

That doesn’t sound like drive train, It sounds more like your pulleys, or belt assembly need maintenance. Get them checked out your engine should be fine.

[@4witekm]

I have run engine with belt removed. Still sounds the same..😉

[@Slowwvqs]

@@4witekm Oh man, I’m sorry to hear that. Have you checked out if it could maybe be the ignition coils shooting a spark to metal piece? Or maybe any of the little electrical components upfront making a little clicking sound? That’s super devastating if that’s the engine honestly :( I hope you can get it resolved!

[@jonas7503]

It sounds like the generator bearing ist dead

[@4witekm]

It is not alternator. Engine sounds the same with drive belt removed.

[@tomaszniedbaa5530]

have you decided to replace the timing chain?

[@4witekm]

No. My '99 ML320 makes that noise for the last 100k.@@tomaszniedbaa5530