Odd odor

My Taurus is a 98 with about 145K on a vulcan engine. About 2 months ago, I had to replace the bank 1 sensor 1 O2 sensor, the one on the side of the engine directly in front. About 2 weeks later I noticed an odd smell eminating from the front of the engine around toward the right side. I assumed it was the O2 sensor breaking in. Mileage has been fine, the oil level hasn't changed, the tranny fluid is fine and red (could use a change due to heavy use this past summer but is essentially fine, doesn't smell burned), there is no loss of anti-freeze, the color is fine, and the engine is running normal temp. In fact, the engine is running fine and the tranny is shifting fine. I've checked the right front caliper for excessive heat and it doesn't appear to have any issues. It doesn't smell like burned oil (dropping on the exhaust? Nope), it doesn't smell sweet like antifreeze, it doesn't smell like burning tranny fluid, or like brakes overheating. Sometimes it smells a little like burning rubber, but its more pungent and metal like. Sometimes it gets strong enough to smell inside the car, but it is coming from the engine compartment. There are no odd noises or squeals. I've checked for rubber hoses or vacuum lines up against hot metal parts and everything seems to be in place. Oh, and no leakage from the power steering pump either, which rules out the rack & pinion. The smell seems to dissipate when either shut off or sitting idle for about 5 minutes. Any ideas would help as this is driving me nuts. :screwy:

Turn the AC on recycled air, not fresh air from outside!
Keep an eye on all fluids for shortage, it's probably just a bad valve cover gasket.

Were the brakes recently replaced? You might be smelling either new brake pads or the anti-rust coating from the rotor.

If you didn't recently have new brakes installed, then I'd suggest you check the brakes to see if maybe one of them is hanging up. You might be smelling really hot brakes. You could walk around the car immediately after driving the car and carefully touch the center of each wheel to see if one is hotter than the others. It would make sense that the smell would dissipate after sitting idle for 5 minutes.

-Rod

Sorry, I just noticed that you wrote it doesn't smell like brakes overheating. Hmmm, what could smell like burning metallic rubber..... I think I'd still be checking the brakes.

-Rod

Thanks Shorod, will do that. It would make sense that it could be the brake pad if the caliper is hanging up and what with the new materials the pads are being made of now days, I would think it would have a different odor from the old asbestos type pads.
I'm also thinking maybe the bearing or CV joint, although I don't hear anything unusual that would indicate the bearing or joint as I don't get any helicopter sound or ginding sound when turning.
I'll keep you posted as to what I find. Thanks again

Well, I got the car up on a rack and got a real good look around. It's the oil pan gasket. Small drip from a corner over the right side cat. I can see where the drip of oil burns off leaving a stain on the CAT cover. I kind of suspected it when I first noticed a drop of oil from the oil pan seal that goes around the front crank cap(?). Not ure what its called, but it looks like a separate seal from the oil pan gasket. So it looks like I should just replace the pans gaskets and seals. Its an odd smell, didn't figure it to be oil on the CAT. Thanks for all the help.

Thanks for the follow-up post! I guess you can no longer trust your nose. ;)

-Rod

Hey there,

Since repairing the oil pan gasket, have you had that odor problem any longer? I'm curious because I've started to have the same problem lately as well -- but mine's a 3.4L V8. I haven't been able to get under the car yet, but similar to you I haven't noticed any fluid level drops indicating a significant leak -- even over the course of a few days.
The odor I'm sensing does smell like scorched oil or hot rubber, but I'm not seeing any tendrils of smoke when the engine's turned-off, and no subtle billows of smoke while it's running.
I do plan on taking it in on Monday to the shop to have a look. I'll let you know what they find.