Fumes in cabin

[sbloxxy]

My brother has an early 944 and he is having a major problem with fumes coming into the cabin; he thinks they seem to be coming from the rear of the car - any ideas?

 

[Fen]

Exhaust or fuel fumes? Assuming exhaust try hatch seal, rear light seals and check for any holes behind the numberplate. If it's fuel check the fuel sender is sealed properly into the top of the tank and the fuel lines over the axle are not weeping.

 

[sbloxxy]

Exhaust fumes - apparently so bad he's driving with the windows permanently open. Remains of a mastic-type substance around rear lights, so perhaps there has been a problem here before?

 

[edh]

It's a very common problem & likely to be worse with the sunroof open - lowers pressure inside & drags in the exhaust fumes.

If it's the lights, you'll probably also be able to see water leaks into the car when you clean it.

The rear lights have a black sealant that sounds like it needs replacing - the light clusters should come out reasonably easily if the seal is that poor. You can buy a roll of the sealant from your OPC for a few quid

 

[Fen]

I'd have expected having the windows open would make it worse as per Ed's mail. Another thing to check is that the exhaust isn't leaking along its length somewhere - it could come in the gear lever hole for example if that is the case.

 

[random hero]

I saw this problem once in a magazine ,i think it was 911/porsche world, aperently its caused by a small breather bottle thats located in the o/s c-pillar (part behind the quarter window)this can crack or the pipes can split but to change it you have to cut the inner body work out and weld it up after fitting a new one. If i get chance i will look in my old magazines to find some exact details. Hope this helps !!!

 

[Guest]

On a previous early 944 I had this, and as suggested above driving with the windows open makes it worse, there is some adjustment to the ¬tightness¬ of the rear hatch closure using the latch pins.

 

[Guest]

I have been battling this same problem on my 84' 944.
I get the smell of fuel in the car though.
I have had the exhaust changed, Bought a New tailgate seal, sealed up around the sender unit with mastic and it still stinks!! None of the pipes are leaking as I also changed The Fuel pump. Out of ideas now!!!

 

[Indi9xx]

Try driving the car with the windows closed and note how fumey it is.

Then crack the window open just an inch or so, and again note the fume level.

If its worse with the window closed, its probably being drawn in through the engine bay through a gromet or the blower assembly

If its worse with the window cracked open an inch or so, its probably the tailgate seals, rear light seals, or a bung or gromet missing at the rear of the car.

Another thing to check for... if the number plate is stuck on with number plate tape rather than screws. If so, check to make sure the screw holes are plugged up, otherwise they will draw in exhaust fumes.

The problem with 944's, is that they develop a low pressure area around the back of the car, which exhaust fumes can lingure in, even at high speeds (which is why the back of a 944 with a rich mixture turns black).. so if you have a leak back there and crack open the window a little or open the sun roof, you oddly enough cause an even lower pressure area in the cabin, which then draws the exhaust fumes through any leaks at the back of the car.

 

[Guest]

Your right, the fumes do hang around the back of the car as i found out when i bought a new SS backbox, it was a little blocked and was putting the fibre from inside the box out the back for a few days, every time i pulled up i had to get out and clean the back, or my car looked like the arse end of a sheep!