[InsuredByGlock]

There is a very noticable rattle during hard acceleration in my 300C. You can actually back off the throttle a bit to make it stop, but it's always there near the top RPM range. The noise even continues and trails off when the car shifts into second. It's a cyclic noise that maps to the RPM's of the car, and to me, doesn't sound right. I took it into a dealer, the tech listened to it, thought something was off, but compared it to another 300C and said they both had that sound.

Has anyone else had this??? Something tells me that this car should not have a rattle when accelerating, but the dealer insists it's normal. I highly doubt it, so could you please let me know if you've experienced this?

 

[jeepgrady]

Just because the dealer found another one with the noise doesn't mean that it is normal. Both cars could have the same problem.

 

["C"for me]

What grade gas are you using? Sounds like "ping" to me. The ping/knock sounds like a rattle most times, if it is as loud as a KNOCK, ya gots real problems. Try better gas, maybe you'll even need to go to a different brand.

 

[InsuredByGlock]

[QUOTE="C"for me]What grade gas are you using? Sounds like "ping" to me. The ping/knock sounds like a rattle most times, if it is as loud as a KNOCK, ya gots real problems. Try better gas, maybe you'll even need to go to a different brand.[/QUOTE]

I'm using 89 from Shell. One of the techs suggested I use 91, though I tried that with no avail. I thought of engine ping, but dismissed that early on... perhaps it's worth another look - maybe my ignition timing is off. It just doesn't sound like ping, though. Also this reminds me of a post http://www.300cforums.com/forums/showthread.php?t=1342 where shaggy talked about the same thing. I also can hear it better with the windows down and next to a curb.

I've read a couple of threads over at lxforums.com that suggest this is a noise that's inherent in the Hemi engines and has been for a long time. Something that quite hasn't been figured out, but usually gets covered up when modding your exhaust.

 

[II kings 9:20]

In a word, no. I have never heard a rattle and don't recall any forum discussion on this vexing problem.This rattle does not sound normal at all to me. Were you there when the dealer "confirmed" a rattle in another C, I doubt it because I doubt they drove another C to really check (please correct me if I am wrong). Has anyone checked an exhaust manifold/flange? maybe the cataclysmic converter? I am sure your 5 star dealer has not checked these simple things first, these guys would do well to remember "common things occur commonly".