My 2002 C230K has a "clatter" noise after the car sits overnight. It lasts for 1-2 sec after the engine starts. If the car sits for 2-3 days, tha noise lasts a little bit longer. It does not make this noise if the engine is warm. Dealer said he could not replicate the noise after a stay at the dealership but I don't know how long it sat. I'm guessing timing chain or supercharger related. I'm still in warranty. Thanks.