Fumes in cabin we have an answer at last !

[944 man]

Its a well known issue Lee. Conversely, if you turn the fan all the way up then even the leakiest and most pongy car will be fume free inside. Its usually the hatch: either the seal or commony now, the glass to frame bond.

 

[ukmastiff]

So what are we saying ? Is it that the window creates a vortex that sucks it in the hatch. Ive gone all round the glass and cut the perished sealent out then ive sealed all round the glass with fresh silacone. The boot rubber looks good and round and ive tightened the hatch pins.

 

[ukmastiff]

Ok i know i shouldnt be working on the car whilst hobbling but i just cant sit
On my butt all day !

I had a very gentle tinker today including further rear light seal , tightened boot hatch pins , temporarily sealed sunroot shut , checked gearstick rubber not only split but detached from surround completely ( temp taped it up). Checked tailpipe its wide oval chrome end does not stick out past the rear bumper.

The result unless im going mad is no fumes until you open the flaming window. Why the hooj woukd you only get fumes on opening the window ?


Regards mas

 

[edh]

The open window (or sunroof) creates a pressure drop in the cabin that causes air to be sucked in from the back of the car through any remaining gaps

 

[ukmastiff]

Ill be damned if i can find the gaps Mas

 

[944 man]

If you fit new or stripped and rebuilt latches along with new pins and a new hatch seal, then itll probably stop. If not then try gaffa taping up the glass to frame area, because your problem will probably be caused by these two separating. Simon

 

[ukmastiff]

The seal 'looks' good and ive seen some bad ones in my time However i knoe how sneeky these things can be. i have really done a job in the glass with the siliconr So ill start by taping tomorrow if i have time then i may have to try a seal Ta Mas

 

[timfield]

What about the drain holes in the bottom of the rear wings? Mine has the pipes from the rear hatch down through them but no seal could they let some in as well? Are they forward enough for no exhaust to get to? In the vortexes that go on at the rear?

 

[ukmastiff]

Firstly thanks to all who have bothered to put in suggestions , i'm sure all of them can cause the said problem and I'm greatful for the help. Today as promised I taped the boot shut. Don't use gaffer tape by the way its not good for your paint as it has nasty strong glue on it. Use 2" wide masking tape ! Anyway , one lesson learned ( as ever) don't discount the obvious or main option. The boot seal may have looked really good and I did tighten the latches but it was indeed the boot.

Now I need to order a hatch seal and hope that cures it as I don't see masking tape as a viable long term modification [] Has anyone used the pattern one its 'supposed' to be as good and half the price ? Regards Mas

 

[Hairyarse]

Glad you found the cause Mas. When I purchase a boot seal for my old square dash I bought it from Porsche Shop. At the time they were by far the cheapest, turned up the next day and was much thicker than the old original one! It was about a foot too long too so plenty of excess left. I did cut it about 10mm too long but even still in a few months it shrunk back and formed a gap of about 5-10mm so leave as much excess as you can get away with []

 

[ukmastiff]

I see what you mean good tip i'll order one monday about £35 i think. Ta Mas

 

[Hairyarse]

...and if you're hatch pins are seized, start soaking them in WD40 now as I bet you'll have to adjust them with the new, fatter seal []

 

[ukmastiff]

Theyre ok as it happens , I need the rubber gearstick gaitor/seal though 19 pounds posted from frazerparts is what ive found so far. Kind of hoped to pick up a sound used one with a leather gaitor too but maybe thats being tight and it will have to be a new one of each. Mas

 

[edh]

The oe seal does not need cutting, you just need to work it really hard into the corners. Bert @ berlyn told me off when I asked him if I could trim the seal as I thought it was too long. the added bonus of a new seal and good struts is that the hatch will open on it's own..

 

[944 man]

...and if you replace or refurb the catches and replace the pins, itll only open on its own when you want it to, after you pressed the button!

 

[Martin Sage]

Result, you are going to replace the gaitor! Also got mine from Frazer Parts, they are very good. You won't be dissapointed Mas.

 

[chrisjcoe]

The open window (or sunroof) creates a pressure drop in the cabin that causes air to be sucked in from the back of the car through any remaining gaps

I'll 2nd that. Occasionally the drivers side boot latch will open, and I only get fumes in the car when the root is open.