Glowing manifolds, what could be the cause?

**Blue Rebel** · 01-03-2010

Hello everyone! Got a question for you guys. On my mothers 2000 grand prix gt 3.8L w/ 117k mi I noticed recently that the exhaust manifolds are glowing. Currently the car has an over cooling problem, and it is -6 degrees out here in WI, yet if i take the car for a 30 min drive at 65 mph, by the time i get back if i pop the hood in the dark i can see the manifolds distinctly glowing. No rotten egg smell, and the o2 sensor has been replaced in the car at least once, but i couldnt tell you when. Now ive never really worked under the hood of this car before, but this just doesnt seem normal to me. So... is it? or should I be looking for an underlying problem? Thanks for any help, she really loves her car, and id like to get this all sorted out asap! Thanks again!

**minichopper6hp** · 01-03-2010

Usually a sign of a restricted exhaust, mainly a plugged cat. converter.

**Blue Rebel** · 01-03-2010

Thats what I thought, but i was under the assumption that a plugged cat will also give off a rotten egg smell when put under load? Is there any way to be sure of this before she gos and spends the couple hundred bucks to get a new one installed?

**Jakegday** · 01-03-2010

yes, disconnect the downpipe from the rear manifold.(good luck) this will eliminate all exhaust restrictions. if you're problem still exists, then you know thats not the problem

**Pittman06** · 01-03-2010

you can also drill a small hole or two (like 3/8) just in front of that cat so when you replace it, it can be welded or covered, and with the holes in it should run fine if the cat is plugged. Saves alot of headaches with removing the dp