Tony_allo

Just bought a used ML350, 2011, Bluetec, currently have ~100,000 km on it.

I found that the car will make a single clunk noise right after the turn of the engine. This usually happens when the car was sitting for a while (like overnight). The first firing up of the car in the morning I hear the loudest clunk noise (one clunk right after starting up). If you turn off the engine and start the car again (the car is still cold), then no clunk noise. During the day, if I leave the car for a while (4-5 hours), on a starting up, I can still hear a single clunk noise, but much weaker.

I have done quite a bit searching online, but I couldn't find a clear answer for this. I know a failing timing chain will make a continuous rattling noise on cold starting up, but mine is not like that ---- just a single clunk right after the turn of the engine.

Any ideas? Thank you!

Maj. Dundee

It could possibly be either of the motor mounts or the trans. mount. Bring it to a repair shop and have them checked out.

Tony_allo

Thanks Maj for the clue.

The shop told me they can't reproduce the problem, sigh... I will do some work myself before waste another day in the shop.

texterted

Could your starter motor be sticking?

Maj. Dundee

Excellent.