walker29

I just picked up a C300 Sport about two weeks ago. The engine has about 800 miles on it so far, and I'm wondering if it's normal to hear the engine rattle for a few minutes on cold startup. Is this normal with MB engines? Is it just because it’s a new motor? Once the car is warm it runs smooth as silk.

The car is parked in the garage, and I live in California. We're not talking freezing cold by any means.

howie

something loose on the exhaust maybe??? Bracket or hanger or something?!?!

walker29

It sounds more like it's coming from the motor. It goes away when its warm and isn't there when I start the motor after I've driven it.

CarGuru

Our C300 Does it too, goes away as soon as the T-Stat opens. I think it's normal. Equally weird is how the exhaust sounds like a small block chevy with aftermarket mufflers for the first 15-20 seconds from a dead cold start.

-Ryan

walker29

Thanks Ryan,

How many miles do you have on your car?

Lakerz4sho

i noticed this in my c300 as well (~1100 miles)..

when i start it up in the morning, i notice that the enginge rumbles a little bit, and even shakes/vibrates the car gently for a few seconds, until the rpm drops and then it runs smooth the rest of the day.

MBTex

I have the same little noise at start up. 2200 miles now and it has always done it. Going to take it in for the "check up" servicing and I'll ask about it, but I believe it is normal.

EDC320

My 2007 C280 4matic does the same thing.
Same engine as the 2008 C300.
Rough idle at cold start then smooth running the rest of the day.

walker29

Thanks for the replies. Looks like this a common issue.

I was starting to wonder if I needed to hit the Slick50 or not j/k

nyca

this is somewhat common in newer cars as the emissions systems struggle to get temperature into the catalytic converters as quickly as possible.

rb23lb

noticed same thing on my c350, seems normal after a few seconds, nothin to worry about right?

dion

I already took my wife's c300 in for first service (3100 miles) and I've noticed it from day 2. I mentioned it to my SA, tech checked it out and stated it's normal.