m a x i m u s

i started the car up early this morning, like at 7am. it was cool weather outside. after starting, i noticed a weird knocking sound, maybe once every few seconds. once it warmed up, it stopped. anyone have any idea what this may be?

also, i noticed that my driver's mirror shakes a bit when im driving over 90mph, whereas the passenger one is rock solid. i felt the mirror after i parked it to see if it felt loose, but it felt no looser than the passenger one. has anyone else experienced this?

thanks.

derspi

I've had the cold knocking sound since day one (car is also an '09 & it had about 30K miles when I got it). Only happens when the engine is cold and sounds like a light mechanical thumping, every few seconds "thump, thump......thump, thump, thump" but as soon as the engine gets warmer, the thumping is gone. On my recent service in May, they had traced it to a faulty/stuck fuel injector and replaced all the injectors. It seemed to do the trick immediately after but the weather has gotten quite a bit warmer so I'm not certain they found the real culprit. I'll have to wait and see if the noise/thumping returns once it gets colder.

CoolBDPhenom03

When you break the sound barrier, the mirror comes off completely!

m a x i m u s

i wonder if that would be covered under warranty. lol.

i have a service appointment monday for something else, so i'll ask them to check on the knocking issue and report back.

CoolBDPhenom03

Actually, for some reason, I also noticed that my driver's side mirror shakes more than the passenger's side. I was told it was some suspension BS, but I think the mirror itself isn't quite as fastened to the whole assembly as it should be. It also produces a "chirp" sometimes upon closing the door. MB says there's nothing they can do about it, but I'm going to have it checked out again.

gometz

I have both those issues too. Strangely enough I had the same chirp thing with my old BMW E90, I could never figure out why.

Only the shaking bothers me. I kind of like to be able to see clearly while driving down the highway (especially looking out for cops behind me before pulling away and the rear window is tinted).

derspi

Please update us back in this thread on what they find and/or fix as I'm skeptical the new injectors did the trick in my case.

Thanks

m a x i m u s

i checked it out again myself tonight, and i noticed that the "knocking" seems to be coming from the tranny area. it's almost inaudible from outside of the car, but if i put my ear down near the gear shifter, i can hear it. i can also feel it faintly if i rest my foot on the accelerator without pressing it, and also in the steering wheel, although that may just be vibration transferring. once it warms up, though, the sound goes away 100%...

derspi

^

I'm fairly certain you & I are experiencing the same problem as I notice the slight vibration in the steering wheel & accelerator. I've always been told by the SAs that all AMGs are known to be a bit noisy and quiver/vibrate a bit more than other cars but I'm not entirely convinced. Seems too easy a cover for MB to deny that there are possibly issues with their engines.