m a x i m u s

hey, guys. i've noticed that when i start my car (the C63) when it's cold (sitting for at least 15 minutes), i get this semi-loud rattle, i think from the engine area, for a millisecond. sounds like when you have a loose heat shield. the sound never happens when the engine is warm. even if it makes the noise on cold start and i turn it off immediately and restart it again immediately, it does not make the sound. anyone have any idea what this is?

Roswell

Dont worry about it, I'm ready to bet it's nothing as our engine makes tons of funny sounds. As long as it's not a loud ticking noise (known lifters issue), then it should be fine.

If it worsen, then you can always have it checked at your local dealership.

Merc63

Lifters bleeding down. Are you using 0w40?

Switch to 5w40.

ZephyrAMG

From what you are describing its not a persistent tick tick but rather a rattle so it could just be that...you heat shield vibrating up against the exhaust tubes or engine or manifold...

Mort

^^^^^ that is what it sounds like to me as well. You are only hearing it when the engine gives an extra kick on cold start up.

jvanbrecht

I had a ticking that was not lifter related.. oil changes, nothing would get rid of it.. (I do my own services and diagnostics that are not warranty related).. It ended up being the power steering fluid being low, the pump was making the ticking sound.. you can try that as well.. (also only when I started the car)

Jak63AMG

I had an experience with a rattle during cold start, it came from the mid pipes rubbing against the cross brace underneath the car, a simple adjustment fix it. If you are using non OEM mid pipes you might want to check it out

m a x i m u s

Thanks, guys. I am hoping and thinking it isn't a big deal. I can live with the slight rattle, and since it is so brief and only when cold, ill wait and see what happens. I have warranty for a while.

Merc-Skycap

Does the noise increase or decrease when you apply throttle?

jvanbrecht

If you have a warranty, there is no reason not to have MB look into it, even if they do not find a problem.

dacls63amg

Possibly a spun crank rod bearing or bad cam adjuster? That will create a rattle sound during a cold start up. Have you put your car in park and pressed the gas pedal? Do you hear any rattle/clanking sound?

m a x i m u s

no rattle at all except for that initial cold start. nothing when i press the gas in park, nothing when i accelerate, nothing if i start it warm, nothing if i even turn if off immediately after cold start and then restart again.

m a x i m u s

diagnosis is typically covered under warranty even if ultimately nothing is found wrong or the problem is not covered?

m a x i m u s

well, I had the cam adjuster replaced in the left bank (driver side) and the rattle went away. now I am having the same issue in the other bank, lol. am i doing damage by allowing this rattling to continue?