air flowing past your open window or open sun hatch creates a vacum in the car.
Air is sucked in to replace the vacume anywhere it can get in. The fact you can smell exhaust fumes means air is being sucked into the car at the rear through the rear hatch or rear light openings or both.
Its as simple as that.

Suggest you remove rear light clusters and put on new foam/rubber seals or sealant mastic.
Next rub vasoline around the hatch seal rubber only and close hatch firmly.
Open hatch and check to see where the vasoline has not been transferred to the other hatch opening. That will be where the fumes are being sucked in when your windows are open.
Try pulling the seals a little off the metal hatch rim so that the seal beds better together. Or invest in new seals

 

My cabin reeks of exhaust fumes with the windows up, sunroof down, and AC vents shut. The smell is focused in the front of the car. The rear seal is fine, as is the shift boot. I'm leaning towards that rubber strip by the cooling fan, mine is smashed in the middle, and some engine fumes could be coming through that open area. Any other suggestions?

 

Good Idea peanut.

Cyrus do your exhaust manifolds leak?

 

It smells in the front because that is where the air in the car is being sucked out and the exhaust fumes sucked in the back are coming to the front and going out past your nose through the window.
Stand in front of a drafty window with a hot radiator under the window and you will feel cold even though you are in front of a hot radiator because the hot air rises drawing cold air from the floor at your feet past your body


Any fumes /hot air under the bonnet is driven /blasted out under high pressure from the base of your windscreen.Thats designed that way to reduce engine underbonnet temps
The only place where fumes will stay is at the back of the car where there is a low pressure area

Somebody get a basic physics book out

 

Where can I get a new Rubber fan box isolation strip?

 

mine was the tire well drain. i got a short caridge bolt (1/2"), two grommets from the plumbing department (pretty sure they were from faucet internals), and a wingnut at home depot....like 3 bucks. make sure you dont have any hatch separation because you'll have a lake in there if you plug it. I also plugged the other two holes that are in the well that run next to the frame rails.

 

bump

Sounds like a great opportunity to add a really nice air freshener and send the Mother-in-law on a really long trip.

bah, bump, bump

 

I get the fumes in the car with the windows UP and the sunroof DOWN and A/C vents SHUT and the recirculation button left alone. Could these be caused by a faulty Rubber fan box isolation strip? If so, where can I get one? Steve?..

Also, I have a minor oil leak caused by a bad main seal. From time to time white smoke will errupt after driving the car, and getting the engine warm.
What is white smoke from under the car, that does NOT smell like exhaust?
Can I put something under where the oil is dripping for a temporary fix to stop that smoke?

 

Sounds like you have a load of problems there Steve and could do with some expert help.
In my experience most Porsche service agents will look at a car and give you an assessment and estimate of the cost of remedying faults without charging for that check over.

White smoke in my experience suggests a blown head gasket. You do not say where exactly it is coming from. Can you not get a friend to drive behind you to check if it is the exhaust?

Why don't you get someone else to drive your car steady on a straight road and use a lighted smoke taper around the cabin to see if you can see where air/fumes are getting in the cabin? You can get these at heating stores They smoulder and give out a coloured smoke and they are used to check for boiler flue leaks and air flow around flues Use a torch if you need to so you can see the smoke Where the air is getting into the car it will strongly blow the smoke and the end of the taper will glow

It could be coming in the door seals for example if you have had a replacement door at any time. The smoke will show you the leaks anyway.

 

Joseph, did you have any luck finding out what's wrong?
We seem to have the same problems (exhaust fumes coming from around vent, heater only blows hot air with that plastic clip fixed.)
I'm leaning towards that fan box strip, does anybody know where I can get one?

Thanks for the info peanut, if I come accross a heater store with that taper, then I'll definatley give it a try.

 

jeez cyrus just set fire to anything then blow it out!...A bit of string forcrissakes or a cigarette
you only need something thats smoking then check in the car while your going along where the fumes are coming in . The smoke will blow strongly away from where the fumes are coming in Whats the point of stripping the car heater out when you haven't a clue where the fumes are getting in.?
Doing the smoke test will tell you exactly where the problem is.

Do me a favour get a roll of 2" paint masking tape and tape around your rear hatch and seal it up then tape around the edge of your rear light clusters where they enter the body .Also tape around the whole of the passenger door. Then tape up the sun roof hatch
it will cost you $2.00 take 10 minutes and if the fumes are still there it will definitly let you know you can eliminate 4 probable causes at a stroke!
If that doesn't get rid of the fumes Then tape up the drivers door and get in the passenger side and try that .
Then tape up the intakes to the heater and climate control intake under the bonnet

Then if that doesn't work start looking at the bulkhead.

 

Okay, I taped up my hatch, both rear windows, sunroof, and the doors, but I'm still getting the fumes. They seem to be coming from around the blower on the top of the dash (the dash vents.) I did the vaseline trick on the rubber strip by the cooling fan, and I got some areas that weren't covered with vaseline after I closed the hood. They were just a couple of small gaps.

I have a question, the PO ripped out the plastic in the door panel. You know that big piece of plastic that should be glued over the door frame, both the ones on my passenger and driver side door are missing. Could this cause the fumes to be getting in through that little air vent in the door jamb?

Where should I look next?

 

Thats great cyrus.
Now you know for sure it isn't coming from the openings you taped, you've narrowed down the possible problem areas considerably. You did do the drivers door as well didn't you ? and most importantly the rear light clusters !........don't forget them

I would try to pull the rear hatch strips up a bit so that the vasoline touches everywhere before doing anything else. Even a small gap will be enough to suck in a huge amount of fumes in seconds once you are motoring along trust me.

Yes the plastic taped to your doors must be inportant for something. Porsche wouldn't put it on there unless it did something. I guess even a little bit of plastic sheet has cost them millions $ over the years!

Make sure you take it right to the very edge and tape it carefully. The air gap you are looking for is probably a lot smaller than you imagine it will be.

Did you tape over the air intakes under the hood that supply fresh air to the car heater and climate control? Its possible this could be the cause especially if you say this is the area where you can smell the fumes.