cabin fumes

[124spiderman]

I'm getting quite a bit of dangerous engine fumes being drawn into the car (when top is up and window open). After some hunting about and experimenting I've discovered that its being drawn via the rear bar mounts - below the taillights and above the tailpipe - (as there is an aperture and some gaps there). Ive tried duct tape but it looks unsightly and peels off.
Is there any sort of cover that should be mounted here as per the fronts. If not has anyone used anything with any success to stop this?
I'm thinking of filling these gaps with Sikaflex, but that's an extreme measure.

[124JOE]

can you post a pic?
im a bit confused

[azruss]

there are a couple of things you can try. you can make a rubber washer out of innertube or some flat rubber. could also seal with urethane foam. may require some cosmetic cleanup afterward. maybe do both?

[Daniel]

did the fumes go away with the duct tape in place ?

[124spiderman]

pic posted:
http://s1119.photobucket.com/albums/k62 ... icture.jpg

[Kent124]

Did you also check for a leak around your exhaust manifold / downpipe?

[RRoller123]

It is likely that the leak is closer to the front of the car. It seems like it would be difficult for the gases to migrate from the back side through the trunk and into the passenger compartment, but through the firewall and heater, etc. there are plenty of opportunities. May be at the interface of pipe to cat-con or the muffler, or at the ex-manifold (although you would most likely hear that pretty clearly, even if small).

[4uall]

Thought I could throw my two cents in. I had a similar issue and it turned out to be a tear in the shifter boot (cover). When I went to replace I found that the rubber gasket was torn, therefore some fumes would come right up and through. Hope this helps.

[azruss]

from what others say, something as simple as a straight end pipe is enough to allow fumes to migrate to the interior.

[124JOE]

ok so i would go to the body shop supply store
and ask for some black body caulk to fill this

and check for the exhaust leak and the crank case vent

[124ADDHE]

Azruss, please elaborate on that, what does one run in the stead of a straight pipe? I too get unwanted fumes and certainly have 0 leaks in the system but do run a slightly angled upward straight pipe. I find that driving with top up and windows open is not reasonable at HWY speeds, only in-town, top down is not a problem.

[mdrburchette]

On the early cars, there is a rubber grommet that covers the bumper mounting hole. If you look on the right top part of this pic you can see it.


I had a problem with fumes getting into my car. Replacing the trunk weatherstrip helped tremendously. I have heard changing the exhaust tip to one that bends down, like the original, helps keep the fumes from being sucked back toward the car too. This may be what Azruss is talking about.

[azruss]

as denise said, many have helped this problem with a down turned tip on the exhaust. I'm also thinking about a small rear spoiler to see if it helps. In my 70, you could smell the exhaust from the passenger seat but not the driver seat. As many have said, you can get that smell from leaks under the hood. I had a leak at the dizzy base that dripped on the exhaust manifold and that burnt oil smell would come in.

[BEEK]

is your crankcase breather open to the air, or is it routed to the air cleaner?

[jpstuckey]

We first ran into this at our little independent Italian specialist shop thirty five years ago. We had a customer with a nearly new spider who had a complaint of sudden onset of severe fumes inside car with top up and a window open even a tiny bit. We confirmed what many have already submitted; that exhaust fumes from behind the car were being drawn in through the bodywork. Since the car was near new and had good trunk weatherstripping and bumper mount seals we tried to ascertain what had suddenly changed. The somewhat fussy owner (washed the car every single day!) had recently been vacuuming the wells on the sides of the back seat where the top mechanism folds and had gotten a piece of clear poly sheeting stuck on the vacuum hose. He ripped the offending plastic out of both wells. We took the plastic trim panels off of another spider and found that there was clear plastic sheeting glued over the opening into the hollow unibody to seal it. After cutting new material and sticking it in place with lots of contact cement the fumes disappeared. I don't think that it is possible to seal the outside of the body well enough to block this path, but it is pretty easy to seal the actual cockpit. I have since used the same technique on many other vintage cars, especially those with aluminum bodies, as there are always a lot of little gaps where the outer skin meets the steel inner structure.