I have a 2005 c230k with 70,000 miles. I have owned it since 2500 miles. I always maintain it, better than most, using Mercedes approved parts and fluids. I have an intermittent rattle during cold starts that lasts a couple seconds. Sometimes it happens on cold start and other times on hot starts. I have searched the timing chain rattle, but I have 1 question. For those that had a bad timing chain, did the noise always occur after the vehicle sat, or was it hit and miss? Thanks

 

the only way to know for sure is remove the valve cover and look at the chain. It's not too difficult to remove. Better to be safe than sorry. You don't want that chain to skip trust me. Also, inspect that the camshaft gears are not worn.

 

Thanks, but does the noise occur at every startup or is it intermittent? Hot, cold? After sitting overnight?

 

Did you have the $12 hose replaced, along with the others? There are some 5 hoses of the same type in total. All should've been replaced under recall. You can bring your VIN to the dealer to see if it was done.

 

I did, but I'm failing to see what this has to do with the noise..

 

A torn $12 hose is one of the causes for rough idling. Not only does it cause rough idling, but it supposedly creates some incorrect air pressure condition inside the engine that eventually leads to the timing chain issues (stretched chain, worn sprockets etc.) you described in the post. Hopefully you had them replaced early enough, and are not dealing with the aftermath at this point.

 

I didn't say it idles rough, nor did I say I had timing chain issues. I'm currently trying to narrow it down