First things first, does anyone else hear "pinging" and "tinging" decsently loud after shuting off the engine. I know all engines settle as they cool but it worries me slightly cause it is pretty loud as I said before. My temp gauge never goes higher than halfway, so I dont think that is the problem.

Another symptom is a smell that occurs after i release from full-throttle. I can't really describe the smell. If you know anything that could help me please let me know. I am hoping it is not too serious. Those are my only complaints, i love the 97 sc300!!! Thanks for any input.

 

That noise is more than likely just your exhaust piping cooling down. Older, stock exhausts I have noticed seem to do that. My exhaust doesn't make really any sound at all when I shut it off.
Is the smell similar to gas?

 

Its totally normal. This is the sound of the catalytic converter cooling down. My car has the same noise, and it doesn't affect anything at all, even passes emissions.

 

Mine does this as well....i'm starting to wonder if the cat's half clogged....

 

It's the exhaust heat shielding under the car...shouldn't need to worry about it.

 

^possibly, but every other car that some through my shop has heat shielding on the exhaust pipes, but I've yet to hear one make as much noise as mine upon shut down.....regardless, all my stock stuff will be gone soon anyways, so I'm not terribly concerned about it.

 

It's perfectly normal, its the metal from your exhaust pipes cooling and contracting. That is that pinging noise you hear. I am certain of this because when I got new piping put it, the noise completely went away.

 

thanks alot for the input everyone! Glad to hear its normal, after smelling it again im almost positive its just exhaust anyways... thanks again.

 

Mine does it loud as well. I shutoff off the car go inside for a bourbon and I can still hear those noises through the closed detatched garage inside the house. Lexus said it was the catalytic converters needing replacing and that they would last 40K more miles before i start to fail emissions tests. Noise is also apparent idling at a light etc...

 

^thats what i figured too.......half clogged cat would put alot more heat into the exhaust system.