knocking noise?

**wicked illusions** · 06-06-2006, 10:14 AM

I just bought an 01SS. car drives great, but I've noticed when I turn my car off after a ride I here a small knocking noise coming from under the car. I dont know if its from the engine or maybe the heat of the exaust(flowmaster) that is causing this. I've hered this same sound on other makes of cars but It kinda trips me out. It almost soung like a small knock on a pan and it does it about every minute after car being shut off and last about for 5 min.then goes away. It also does it when car is cold and I start it up. I am also pumping 87 unleaded fuel can this be a reason??? Is all this normal?Iam I just fraking out? someone help please..

**2001NBMZ28** · 06-06-2006, 10:33 AM

My car makes some tapping sounds after shutting it off when it's cooling down - has always done it since new. I think mine is just the cats/exhaust, not very loud.

**wicked illusions** · 06-06-2006, 11:31 AM

maybe its normal

**BobsSS** · 06-06-2006, 02:25 PM

Does it do it when you run a couple of tanks of 92+? These cars are not really made for much less than that.

**^BiG DADDY T/A^** · 06-07-2006, 04:26 PM

Dont Worry Its Just Your Exhaust Cooling Down From The High Temps Whaen Its Running

**wicked illusions** · 06-07-2006, 05:20 PM

but it also does it when the car is cold.

Ratdaddy07 · 06-08-2006, 09:17 AM

Temp changes in the cats and maybe a few loose pieces in the honeycomb. Gut them babies and let that thing breathe ( no I"m....I'm just serious). Anywhoo, start running higher octane fuel or you will have some real problems.

**illcul8troffcr** · 06-08-2006, 11:21 AM

Originally Posted by wicked illusions

I just bought an 01SS. car drives great, but I've noticed when I turn my car off after a ride I here a small knocking noise coming from under the car. I dont know if its from the engine or maybe the heat of the exaust(flowmaster) that is causing this. I've hered this same sound on other makes of cars but It kinda trips me out. It almost soung like a small knock on a pan and it does it about every minute after car being shut off and last about for 5 min.then goes away. It also does it when car is cold and I start it up. I am also pumping 87 unleaded fuel can this be a reason??? Is all this normal?Iam I just fraking out? someone help please..

When these cars say required to run high grade fuel in them and you put regular in it they say use the high grade for a reason. The knock will be louder using cheap shit. Even with as high as gas is out here in Vegas and the fact that they dont even offer 93 or 92 octane .. the highest is 91.. I wont use anything less than the best I can get. I can tell a difference in just the 91.. I cant imagine using shit gas