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Llamaguy · Joined: 02 Jul 2003 Posts: 711 Location: Indiana

I noticed today that there was oil sediment in the front half of the TB and in the larger hose connected right next to the TB on the main air snorkle. I'm not sure, but I thought that that hose went to the brake booster and the like.

There's no oil on the back of the butterfly, so I know it's going toward the intake, and that's the only place the oil could be coming from. I also have a curious oil spot on top of the motor right under that connection so I assume that's where it is coming from.

So where's the oil coming from and how do I stop it.

PS, the motor doesn't smoke at all.
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1987 924S Guards Red
1997 Suzuki Tl1000 Supersport

Paul · Posted: Mon Sep 25, 2006 8:36 am Post subject:

Oil breather?
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White 87 924S "Ghost"
Silver 98 986 3.6l 320 HP "Frank N Stein"
White 01 986 "Christine"
Polar Silver 02 996TT. "Turbo"
Owned and repaired 924s since 1977
Porsche: It's not driving, it's therapy.

Llamaguy · Joined: 02 Jul 2003 Posts: 711 Location: Indiana

I traced it back to something under the back of the intake manifold.

is the oil breather suppose to be putting oil into the intake though?
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1987 924S Guards Red
1997 Suzuki Tl1000 Supersport

Chrenan · Joined: 15 Jan 2003 Posts: 3903 Location: Canada

In the old 924 yes, it puts oil vapours back into the intake system to re-burn. Not sure about the 2.5 though.
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1987 951 - M193 Version for Japan

Paul · Posted: Mon Sep 25, 2006 11:09 am Post subject:

The new ones too!

The oil filler tube also has an oil trap that has a hose that runs to the rubber intake hose that attaches to the TB.
_________________
White 87 924S "Ghost"
Silver 98 986 3.6l 320 HP "Frank N Stein"
White 01 986 "Christine"
Polar Silver 02 996TT. "Turbo"
Owned and repaired 924s since 1977
Porsche: It's not driving, it's therapy.

pdubb · Joined: 27 Sep 2006 Posts: 3 Location: San Antonio,TX

I was reading somewhere that what you found could be blowback - which is a symptom of cars with worn rings/valve guides. The problem supposedly occurs in alot of high mileage cars - that might be the problem. If you have low compression that may be it. Just a thought!

Llamaguy · Joined: 02 Jul 2003 Posts: 711 Location: Indiana

no, the oil is only on the front of the butterfly and then only up to the point that the first vacuum line attachs so it has to come out of that hose. Must be the oil breather. Would it hurt anything if I disconnected and sealed both hoses?
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1987 924S Guards Red
1997 Suzuki Tl1000 Supersport

Chrenan · Joined: 15 Jan 2003 Posts: 3903 Location: Canada

I wouldn't seal the hose coming from the crankcase, you want the crankcase to be able to breath a bit, otherwise crankcase pressure will get too high and cause oil leaks. Supposedly a small vacuum in the crank case helps the rings stay seated, hence the routing through the intake. However, this does draw crap back into the engine. I've always wondered if the "helps the rings stay seated" story was just a ploy by environmentalists to have crankcase gases reburned as opposed to vented. In any case, at the very least run the hose from the crankcase into a catch can so there is still breathing allowed.
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1987 951 - M193 Version for Japan