Exhaust smell when driving w/ windows down

[nexus08]

I've been chasing this problem for awhile. My car has a strong smell of exhaust in the cabin. It doesn't smell rich, just like exhaust. It isn't there if the windows are up and the vent is blowing. The smell is there if I'm stopped or moving, and is just about as bad at highway speed as any time.

I've come to the conclusion that it is probably some kind of body leak that is causing exhaust to be sucked in from the back of the car due to a vacuum created by having the windows down. Google tends to agree with me.

My question is, do you guys know is there a common leak area I should be checking? I see the old Z's had problems with the hatch seals, and tail light seals that would cause this. Is this a problem with this car too?

Thought I would check to see if you all had any ideas. I'm planning on giving the method described in this link a try and will report back what I find.

http://www.classiczcars.com/forums/exha ... olved.html

[nexus08]

Ok, got a chance to do this, and definitely found the source of the smell. I had actually suspected it was the source...

I hooked up the shop vac as described in link, and then held a burning cigar near the places I suspected might be a leak.

For me it was a large hole rusted through the passenger side fender well. With the shop vac on, the cigar smoke was sucked right up into the hole and the car.

I temporarily plugged it and the exhaust smell is gone. I'll have to give it a more permanent fix later but I'm very happy to have found the problem.

I had seen lots of threads on here about exhaust smell, with a lot of check engine suggestions. I think this is a good thing to check if you are having problems with exhaust smell especially with the windows down when your driving at highway speed.

Basically what is happening is that with the windows down and at speed, a vacuum is created in the back of the car that sucks the exhaust in through the holes/leaks.

Hope this helps someone else.

[Ace2cool]

Thanks for the follow up. Glad you got it sorted as well! I would have never thought about something like that.

[t.mcginley.jr]

That's a really good method! I would've never thought of that

So where is the rust hole at? in the wheel well?

[nexus08]

That's a really good method! I would've never thought of that

So where is the rust hole at? in the wheel well?

Yes, right behind the rear wheel, behind the bumper cover.

I've circled the location on this car (not my car, fyi).

[nexus08]

Just more FYI... but here is my car the day I bought her. I've done a little work on her since but she looks more or less the same.

[t.mcginley.jr]

My 90 NA had a big rust spot in the EXACT same place but on the drivers side. I cut out all the rust and welded a new piece of steel on it, body filled the edges and undercoated it. There are also plastic vents that come out close to that spot, but they are there for a reason. Something about letting the interior breathe when the cars closed up.

[nexus08]

My 90 NA had a big rust spot in the EXACT same place but on the drivers side. I cut out all the rust and welded a new piece of steel on it, body filled the edges and undercoated it. There are also plastic vents that come out close to that spot, but they are there for a reason. Something about letting the interior breathe when the cars closed up.

Yeah I noticed those vents too and thought "well dang, they intentionally put a hole there" but then realized that the vents are designed only to let air out, not in. Now if those vents were messed up it would do the same thing as the hole is doing on mine.