Did a Seafoam treatment the other day and put some into the brake booster vacuum hose. While doing so, I noticed some of the exhaust smoke coming up from behind the engine where the rear spark plugs were (It's the V6 2.8L). Would this just be a bad exhaust manifold gasket, or something worse? It only did it for a short time and I didn't notice anything else unusual.

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My Fiero: 1986 Pontiac Fiero GT, V6, 4-speed manual

could be anything

cracked manifold, broken bolt, bad pipe, bad y-pipe connection, bad gasket.

Do you hear a ticking noise?

Or you just dripped a little on the engine when you were putting it into the break booster hose. Larry

I wouldn't worry too much, as stated, you may have just dripped some Seafoam onto a hot manifold. If it makes you feel any better, I've been running my car with a cracked front manifold since I bought it 5-6 years ago. I've gotten used to the ticking and my wife says it wouldn't be my Fiero without it. I don't fix it because I have nightmares of broken manifold bolts

[This message has been edited by fastblack (edited 06-24-2014).]