FLOAMG

Hi if someone could please help me on this it would be greatly appreciated. I’ve been hearing a slight rattle on startup my mechanic is telling me it is a timing chain issue and if it isn’t replaced it could be catastrophic. It doesn’t sound like it rattles every time but he said it’s a huge job and expensive. 155k miles has anyone dealt with this ??? Thanks in advance

poots

If it rattles for a second or two on cold start and then disappears, it's most likely cam phasers, time to replace the the lock plate.

Accidental L8 apex

Definitely cam adjusters. Known issue on cold starts only. Haven't really heard of timing chain issues with these, but that's a decent educated guess from someone that doesn't specifically know these engines.

poots

https://www.63motorsports.com/faqs-6...-adjuster-m156

Some resources and reading for the cam adjuster plates that usually fail.

FLOAMG

Rattles for a second or two then goes away but has been getting progressively louder now it sounds terrible. If started then stopped and started again no rattle. Only when cold and only on initial start up. Thanks to everyone who is replying. If it is cam adjusters/phasers could this be catastrophic if not immediately addressed ?

poots

I don't know if this is going to be catastrophic if left ignored on the M156 but the noise is literally the rotor lobes inside of the cam adjuster slamming into the stators until the engine builds enough oil pressure. On many other cars it can (and has) failed catastrophically. This needs to be addressed ASAP and it's recommended you do not drive the car until it is fixed.

roadtalontsi

"huge job" can literally be done in about 4 hours or less. lol. time to find someone who knows how to work on your car.

FLOAMG

👍

poots

Nope, no need to remove the engine. Just air boxes, valve covers, and cam gear covers. The only special tool you need is the timing lock kit to hold the cams in place and time it properly. It's a 4 hour job. Engine stays in the car. Find another mechanic that knows this car.

FLOAMG

how big of a job are the cam adjusters and is it worth it to do both at the same time then ?

FLOAMG

it’s going to another shop in the morning for a second opinion sounds like I’ll probably go with that one. 😂 thanks

DRBC43AMG

I would certainly do both sides in one go and when in there, a good inspection of the cam lobes is a must, specially the intake (top) cams as they have less oil lubrication. Why not also do the tappets at the same time with upgraded BS ones. Not cheap but with all these goodies you will have total peace of mind going forward.
M156/9 — M156 Shop M156 Camshaft Adjuster Mercedes-Benz AMG (63motorsports.com)
M159 Mercedes-AMG Weight Reduced Black Series Lifters Tappet — 63 Motorsports Inc.

FLOAMG

I should’ve clarified when I said both I meant cam adjusters and timing chain but the tappets are a good idea.

poots

it's unlikely you need to change the timing chain, it's usually just the cam phaser plates themselves.