akbro93704

I know this has been discussed before....but this is my exhaust during a cold start. It sounds more obvious in person....but is this the same sound that everyone else has been noticing?

http://www.youtube.com/watch?v=Cf8sYKZGiac

RickP330

Yes, I hear that popping as well. Additionally there is a "knocking" sound - coming from under the hood I hear when I do a "hot" start. After the engine is nice and hot, let it sit for 2.5 hours and then start it listening up front. You may or may not hear a "knocking" sound.
Rick

C300Sport

Sounds pretty good...and pretty normal to me. I admit it does seem to have a touch more "aftermarket exhaust" sound than mine, but I only have 3K so far. I wouldn't worry about it unless you get a noticeable engine misfire which can cause big pops as the raw fuel hits the catylist...but not on a cold start.

delirium

My C350 sounds really quiet compared to that... however, I am always inside of the car when i start it up...

micropower99

Sounds normal IMO.

C300Sport

Yeah, I know what you mean...but I have checked it our a few times while idling in the driveway.

akbro93704

Yeah, I hear that knocking sound too on a warm start....it doesn't occur all the time though. My dad's ML350 does it too. I think it's normal for these V6's.

Also, I didnt notice my exhaust was making this noise until I saw a thread about it on here, and checked it out. But hey, I think it sounds pretty cool haha.

RickP330

I think so too, I got a W203 loaner and it made the identical noise.
RP

CarGuru

I agree and wish it sounded as throaty once it's warmed up too. It must be a V6 thing because my VQ40 in my '08 Nissan Frontier sounds just like it when you start it cold. It's basically the fast idle valve closing one of the butterflies in the intake track to keep the car from dieing when cold starting often called the (Closed loop cycle) perfectly normal and just about every modern car does it. It's more pronounced on cars with a dual or true dual exhaust because of the sound waves cancling out.

-Ryan