Exhaust fumes...

[dubois]

it seems that this is a constant battle with some of the 02's. I don't have a problem anymore, so I want to share my findings.

It only takes a very small pin hole in your exhaust system to cause a headache - pun intended. Those can be best detected by going around with your hands and feeling the gases escape. Tried other methods, but still this is the most effective. Yeap, you will get zapped once or twice.

Some trunks don't actually fit the opening that well, so if the gasket is old, there will be gaps and exhaust can come in that way. Adjust to make sure there is contact - test with a piece of paper for friction.

Even if there is a seal, the bottom part of the gasket, may have come unglued, and exhaust will come in thru the bottom. Go around and check by lightly lifting the gasket.

The joint where the two end of the gasket meets, can also be problem. RTV the joint to eliminate the problem.

There are a thousand holes in the rear body panel - each one of them must be sealed, or the screws tight so there is no possibility of gas penetration. Don't forget the bumper holes and reflector holes.

The taillamp gaskets, get brittle and yes they will allow gas to come in. This was what ultimately solved my problem a year ago.

My next project is to find how to adjust the trunk for a better seal, any ideas? I think part of the problem is that some of these cars have at one point of another been rear ended and the trunk opening has been distorted.

[jerry]

i would imagine that a leaking trunklid problem would be exacerbated if the car had speaker holes cut in the rear shelf. furthermore, the spongy blob stuffed into the wheel arch opening should be intact. i'd consider those interior openings our 2nd line of defense.

[JackBennett]

I finally got around to putting rope caulk and closed cell foam around the speakers in the rear hat shelf and it turned out to be the trick. No more fumes at all. The gap was tiny but that's all it took I guess.

[Napes]

My ' 75 probably has all the listed possible paths of exhaust and/or fuel fumes to get into the car, yet, after replacing the fuel tank sender gasket, I have no fumes whatsoever from either of those sources in the cockpit. And none of the original fuel recycling piping is intact on my car - screws in the end of all hoses that have to do with that system. My trunk gasket seems to be forever getting knocked loose by people putting heavy suitcases or boxes of food into the trunk, my hat-shelf speakers are not tightly sealed by any means, and on and on. Maybe a source of exhaust fumes comes from the downpipe-to-manifold gasket leaking. Seems every time I've had the downpipe off the gasket looked terrible, and was always replaced. Just my 2¢ worth.

Bob Napier

[jgerock]

I wonder how the length of the exhaust/muffler tip and where the exit point from the rear affects the smell if you have leaking gaskets and holes in the trunk.

My car stunk to high heaven of gas fumes until I replaced the pickup O-ring seal with the correct BMW part. Now I can fill the tank all the way up and not have any fumes in the trunk or cabin (my car also has speakers in the rear deck).

I wonder if adding a set of the foam speaker "mufflers" that Crutchfield used to sell would help.

[Napes]

In line with what Jim mentions I was going to say that my muffler chrome extension lines up with the back of my bumper, which also eliminates any exhaust staining on the underside of the alum. bumper.

Bob Napier

[ole1.6]

Changing back to stock side exhaust from the Anza center style made 90% improvement to the staining and trunk stink. After reading about the speaker cut-out potential I think that may have caused my headliner to inflate during certain conditions. Namely driving fast with the windows open. Thanks guys.

[roadhog0]

You can also check the exhaust flange under the car where the down pipe and rear exhaust meet. That is and was where mine leaked. It is very minimal though now. It all started when my exhaust fell off there on the drive home one day. That was a LOUD but very nice sounding ride!

[Guest Anonymous]

and FWIW, no matter how sealed up the trunk is, there is an open path into the cabin from the vents that are at each lower side of the rear window. Might be worth plugging them temporarily to see if fumes are coming in there.

If there are fumes in the trunk, besides trying to keep them out of the cabin, it'd be important to keep them out of the trunk. So don't just worry about speaker holes, etc, try to find out how they are getting into the trunk in the first place. I'd start by looking for exhaust leaks and holes in the floor of the trunk - in the wheel well and around the gas tank.

If exhaust is coming in from the front of the car, fix the leak and check/replace all the seals around the hood and the surfaces it mates to.