I recently bought a 2002 C230k Coupe. I absolutely love this car, and can't believe there are not more on the road. I do have one question, when I start it up on a cold (less then 40 Deg F) in the morning it has a loud sound like an exhaust leak until about 3-4 mins after it has sat idling (I start the car and let it idle to warm up before I leave) then the sound goes away, in fact its funny I stayed out there in the morning with the car and the noise went from noticeable to quite just like someone closed a switch. What I was wondering, is this normal, is the noise an air pump for cold starts with reduced emissions or something.

Thanks

Charles

 

3 or 4 minutes? Its usually about 40 seconds. Its the bypass routing hot air from the supercharger to the catalytic converter. Youre correct, its an emissions thing. I think it helps em meet ULEV or some ****.

 

welcome!

umm..if it sounds kinda rattling...in the engine, hmmm,.,. iono it happens to mine as well every morning. but i have no idea wut it is...or if it is also normal or not.... i dont have the answer (sorrie) .. i wanna know wut it is also.

 

40 Secs maybe right, I did not time it until this morning. It sounds like that is the anwser with the bypass. Thanks.

Charles

 

i think i have the same noise and it happens before i even put in the key, in fact, it sounds like air is moving through the vents as soon as i open the door, dunno

 

I know the bypass valve noise, but recently my car has developed a noise from the engine bay... a rattling that goes away after the engine has warmed up abit. A search on the Internet yielded a wealth of information regarding worn out belt tensioner pulley rubber shocks. I took my car into service and told the service guys to take a look and viola! my rubber mounts were half eaten away and cold tight belt would vibrate the tensioner and rattle it against the engine block.

All has been fixed under warranty.

Cheers,

3point

 

does that mean, i have to take mine also??...uhh..wut should i tell my advisor....just rattling?

 

Can you give me more information about this?

Thanks.

 

Never heard of this issue before. Interesting. There must have been witness marks on the block I assume?