Exhaust smell in car – pls help.

[jack1986]

Hi all,

I have a 1986 911 Cab with the factory heat exchangers and a Dansk muffler. I have had it for five (loving) years now, with few problems.

Recently I have detected an exhaust gas smell in the car. The very strange thing is that I can only smell it when I take my foot off the gas and decelerate. I can turn the heat and fan on full and smell nothing, but at 40 mph in gear I come off the gas pedal, I smell it. It does not seem to come through the heating system.

I know this is very dangerous and I need to address it.

Any Ideas?

[twin plugged targa]

1st thing I was going to suggest from the title of your problem was the heater!.
I still beleive that this must be the route of your problem and maybe the racking of the engine when you decelerate opens up a hole or leak which goes into the heater system.
I don't see that it can be anything else, maybe someone else can be more exact.
Good luck
Ben

[Rot 911]

I would be surprised if your heat exchangers had holes in them from rust as they are stainless steel. When I took the ones off my 86 with 133,000 they were in great condition. Are you sure you are smelling exhaust as in carbon monoxide or are you smelling burning oil? I suspect one of two problems, the first would be an oil leak on the heat exchangers. Something more serious would be bad valve guides. What makes me think the valve guides is a possiblilty is that you only smell the exhaust when you decellerate in gear. Do you also see a puff of smoke come out the exhaust when you decellerate?

[face-ache]

on my car I started smelling exhaust at intermittent times at idle. I discovered a hole rusted in cat by-pass pipe, the boxes around the x changers do not usually seal 100%, you'll notice small gaps were the boxes crimp around the header pipes. mine was getting sucked in on the drivers side.

[KobaltBlau]

Is this with the top down?

....




Maybe the exhaust is catching up with you! I kill me.

[jack1986]

Is it possible that the exhaust gas is somehow finding it’s way into the vehicle once expelled out the tail pipes (I only smell it when the vehicle is moving)?

- or –

Is there a very high probability that a leak exists?

--------------------------
1986 Carrera Cab

[jack1986]

Sorry,

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