1971 Cutlass 350 Convertible. Car sat a week & I started it & left it running in fast idle in the opened garage for about 5 minutes to move it over for winter. Smelled a strange thing & it seemed like brakes or clutch. Neither of which it could be. Shut it off & the smell hung around a long time. I finally figured it was rubber. There was some smell at the firewall but most at the rear of the car at the open door. I looked & saw nothing laying on the exhaust. Could this be a frozen pulley w/ a belt running on it? I'm not checking it inside 'til I can back it out. Looking for thoughts of where to look. I can't think of anything on these cars (no converter) to get very hot. Ran great no backfire.

 

I would think if it were coming from a pulley or belt you would have heard it in addition to smelling it. Especially if the smell was that strong. Did you pop the hood and look for signs of anything out of the ordinary?

 

You might want to check your exhaust system. Road debris may have gotten trapped under your car.

 

Next will be a thorough check underneath. Probably exactly what you said. Nothing obvious from a quick look. If I find nothing against the pipes or mufflers, I'm speculating a mouse got into the exhaust. This happened on a Honda I bought. That wouldn't start. Mine runs fine. Does a mouse nest, burning up sound possible?

 

Certainly sounds like a belt or pulley issue. Check for any signs of wear or obstruction around the pulleys and belts. If the problem persists, seeking a professional mechanic's opinion would be wise.

 

Concluding it's the smell from Stabil put into the tank at the last fill up for winter. I used 4 oz in a full tank. The mowers have a smell in spring at start up. It seems reasonable a car would do the same, especially in a garage. All of the belts are tight enough & pulleys are free to turn. Nothing visible against the exhausts.
Al