heat off of manifold

[phaertes]

Anyone want to make a guess at a diagnosis? '92 240sx

I'm getting a LOT of heat off of my manifold the last month or so. The heat shield was taken off a few months ago (as most people do eventually when it starts to rattle), and for the most part didn't notice anything.

Lately, however, the heat coming off the manifold is making the floor of the driver's side, right where my heel rests when it is on the gas pedal, very very warm. Like, warm enough to heat up the rubber in my shoes and make the rubber soft.

Muffler shop put it on the hoist, felt the pipes -- seemed ok -- and said to put a heat shield on it. But the amount of heat I am getting now is fairly recent.

Any ideas why the manifold is getting so warm? It's a very concentrated spot... it's not like the whole length of the exhaust is getting this warm. Was thinking of giving my engine a nice SEAFOAM bath and a tune up in the near future anyways, but if someone has an idea as to cause of this heat, that would be wicked.

Also, sometimes getting a slight smell from the exhaust... oil burning maybe? I don't get any coloured smoke out of the exhaust though. Someone else suggested there might be a leak causing the heat, but I don't even know where to begin to look to see if this is true. Fluid levels seem fine.

Exhaust has always been a little noisy, and that still hasn't changed.

Sometimes get the good ol' sulfur smell when I am accelerating up a hill. Cat converter seems ok, but the exhaust noise (which has been there for quite a while) may be coming off from there.

gonna do a check on the 02 sensor.

Oil light comes on whenever I start the car, but disappears after 1 or 2 seconds.

Those are the only odd things I have noticed.

[NISTECH]

Is the ambient temp higher now then it was when you first took it off? This might play a part in it. I would have to say the same as the muffler shop,put the sheilds back on. If you engine was running lean it could run hotter as well your O2 will reveal that. If you have a restriction in your exhuast it will get much hotter in front of the cat. You say your exhuast noise appears to be from the cat.You do realize your cat is a thermal reactor right? It will get hotter then the pipe in front of it is due to the atomic reaction in it [combining O2 with HC and CO to create H2O and CO2]This generates a serious amount of heat in the paladium substrate inside. If you have a leak or a melt down condition the heat in the general area of the cat will substantially increase.

[phaertes]

Ambient temperature is warmer from when I took the shield off originally. In fact, the heat on the floor became much more noticeable as the weather improved... hmmm...

It is NOT the Cat that is getting hotter, or even the area around it, so I don't think that it is the problem then (phew!).

So from what you say, if COULD be a blockage in the exhaust somewhere. The engine temp remains pretty constant... I have never noticed it getting hotter. I am getting the car tuned tomorrow and will replace the o2 sensor at the same time.

I'll try to see if there is a blockage somewhere, and barring that, just get a new heatshield put on.

Thanks so much for your help!

[NISTECH]

actually what I am saying is since the outside temp is warmer there is less cool air flowing up under the car to keep the floor boards from melting your shoes! You may not have anything wrong with the car it self,other then the obvious missing sheilds.