Clanking while cooling and smell

[Ansible]

All,

Last night I took the baby ('91 stick) out to run an errand - probably three miles out, three miles back. When I got to the store, the car smelled "hot" when I got out.

When I got home and put the car into the garage, it smelled really hot. It reminded me of the smell years ago when I drove over a plastic bag and it melted onto the catalytic converter (different car).

Not only that, but standing next to the car in the garage, the rear of the car was clanking - like thermal contraction, or someone was banging on a part with a metal hammer. It was loud - clank! clank! clank! It went on for about 10 minutes gradually slowing down...

I popped the engine hatch. The sound and smell did not seem to be coming from the engine compartment, but from under the back end. I peeked underneath with a flashlight, but didn't see anything obvious. This morning I checked the car ... no fluid leak.

Any thoughts??

 

[hofffam]

My '97 makes a lot of "thermal" noise when I shut it off. It sounds like metal shrinking/flexing. But the car doesn't smell hot nor is it hot. The noise seems to be all coming from the exhaust area under the rear of the car. I assume it is heat shields, catalytic, exhaust etc. all cooling and changing dimensions slightly at different rates.

 

[Ansible]

Thanks - you may be right. Interesting, although I use the car nearly every day, I've never heard it clank like that before.

 

[Bravo]

Never seen it in an NSX, but have seen other cars, with damaged or clogged catalytic converter matrix...

 

[Ansible]

Never seen it in an NSX, but have seen other cars, with damaged or clogged catalytic converter matrix...

That sounds nasty. Any way I can (easily) test for that?

 

[Ansible]

Acura of Serramonte (in Colma) found the problem: A bad coil. That was not only caused the bad smell (unburned gas), but also explains some other issues. Whew!

 

[gt_nfr]

I remember the last time I smelled something hot...