Ugh...I just found rust. What is this part?

[speeder]

Like the others said, the surface rust on the tin is a big nothing, but the rubber seal is not. I learned back in my VW days that the rubber/tin seal is crucial to the cooling of these engines! Without a tight seal around engine bay, fan is sucking super-heated air and just recirculating it. With 930's excesive heat in that region, I would imagine that they go through that seal pretty regularly, but I would still replace it whenever neccesary.

It would be a real easy DIY job to do a partial drop, (2 bolts and a floor jack w/ a piece of plywood), replace the seal and the motor mounts at the same time. Where are you in So. Cal.? Maybe I could come down and help you if you need it, drop me a line.

Edit: Just looked at your ID, Thousand Oaks is close enough to me.

[dean]

If you are getting exhaust smell in the cabin under boost I think you have a cracked heat exchanger.

[Emission]

So, is this the part I need to replace to fix that gasket?

Engine Sheet Metal seal, 3-sided, 911 Turbo (1976-89)
H-504-170-01 $136.00

I also need two engine mounts...

I don't think the heat exchanger is broken since I don't get any exhaust smell in the car when the heat is on, only when it is under high boost.

[dean]

Like I said if you get exhaust smell with the heat on under high boost I think you have a cracked heat exchanger

[Emission]

Originally posted by Blown
Like I said if you get exhaust smell with the heat on under high boost I think you have a cracked heat exchanger

OK, I don't count anything out.

Do I need to pull the exhaust to check? If it is cracked, is this the perfect excuse for a full B&B? Oh, my wife would kill me...

[dean]

Mine are cracked also and I am going to go with SS heat exchangers. You could tell the wife that it is a safety issue. CO is very bad

[Emission]

I just thought of an easy way to check. I have a home CO detector/alarm that is battery operated (just like a smoke detector). I think I will need to pull it off the wall and take it for a ride with me!

My car is out of commission for a pedal re-build right now. I will post my findings this weekend. Thanks for the insight!

[dean]

That might work. You could also go to your local fire dept. and get a fireman to ride with you while he is reading a portable CO meter. You will have to scare the hell out of him, but that's ok.

[logician]

Hi Emission,

> So, is this the part I need to replace to fix that gasket?
>
> Engine Sheet Metal seal, 3-sided, 911 Turbo (1976-89)
> H-504-170-01 $136.00

Yes, exactly. There is also a seal along the forward side of the engine too, but it almost certainly in good shape, because it doesn't get cooked.

Regarding exhaust smell, how exactly does it smell? Does it make you dizzy, i.e. CO? Or is it more like gas/oil fumes? If it's just gas/oil fumes, then it would not be a problem with the exhaust system.

I agree that exhaust smell would point to a problem with the heat exchanger. However, another possibility is a broken exhaust gasket or cracked exhaust pipe, combined a way for those fumes to get sucked into the fan, i.e. your cracked road seal. One of the problems that I discovered when I worked on my 930 engine recently was an exhaust gasket that had burned through, which was presumably allowing gases to escape at the flange.

Does the smell happen when the heat is turned off? Fumes from a crack in the heat exchanger, or getting sucked into the fan, would be worse when the heating system is on.

I like the idea of using a home CO tester -- good idea!

-Juan

[Emission]

I can only smell it under full boost, with or without the heat. I rarely run the heat, so I know it happens just as often with the heat off.

Originally, I thought the smell was along the lines of raw fuel... but then, as I started to really think about it, it started to smell more like a fuel/oil mix. It does not smell like it is burnt, nor does it smell like exhaust. I am getting a fuel mixture sensor, so I will be able to see if it is running too rich under boost.

Tomorrow, I will be under the car replacing the clutch cable. I will get a chance to check out the exhaust at that point. I am going to start a new thread on this (this is getting off the original topic).

Thanks so far!

[logician]

Hi,

> I can only smell it under full boost, with or without the heat. I
> rarely run the heat, so I know it happens just as often with the
> heat off.
>
> Originally, I thought the smell was along the lines of raw fuel...
> but then, as I started to really think about it, it started to smell
> more like a fuel/oil mix. It does not smell like it is burnt, nor does
> it smell like exhaust. I am getting a fuel mixture sensor, so I will
> be able to see if it is running too rich under boost.

If the heat doesn't affect the intensity of the smell, then I would say it is not related to either the road seal or a possible leak in the heat exchanger, or exhaust system.

So, I have a similar sort of smell in my '86 930 as you describe -- a sort of stale fuel smell. It doesn't smell as sharp as fresh fuel. Actually, the smell is a lot like what you smell if you put your nose up to the fuel hoses in the luggage compartment, just foward of the brake servo. The smell is most noticable when you open the sunroof. I suspect some kind of fuel leak, but haven't narrowed it down. Does this sound like your problem?

My '85 Carrera had a fuel smell that turned out to be a leaking fuel line at the front pump. It puzzled me for a whole year, until one day it finally failed enough to drip gasoline on the ground right under the pump, which exposed the problem.

-Juan

[Emission]

Originally posted by logician
. "...It doesn't smell as sharp as fresh fuel. Actually, the smell is a lot like what you smell if you put your nose up to the fuel hoses in the luggage compartment, just foward of the brake servo. "

It does smell like stale fuel - the same smell the car fills the garage with when it is parked after a hot run. I keep thinking it is fuel related - especially considering I smell it under hard boost.

[john70t]

The CO you will never smell...until too late. Many people perish every year from bad stove/water-heater mixtures (a yellow flame is dangerous-too rich). The symtoms are dizzyness and nausea in small qualtitys. The burning nose is from HC's which are raw gas.
That smell could be from raw gas in the hot tailpipe from a way over-rich mixture/misfire under full load if not something else.
Just remember-"Rust never sleep's". put some rust converter on it if nothing else.