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langmd · Joined: 30 Sep 2020 Posts: 8 Location: Minnesota

On the 931s turbo cold side there is a square cap on each side that bolts on with 4 bolts one side has an oil return line I am seeping a little oil out of bottom on both sides. I ran a smoke test and have a leak at main intake plenum and on the crankcase breather line that runs under intake into block. Also previous owner deleted the Y in that line so not sure where that line would run or if needed? Any help is appreciated as new to car and a little clueless..

langmd · Joined: 30 Sep 2020 Posts: 8 Location: Minnesota

Sorry not main intake. The leak is at tube connecting turbo to intake that takes that one big o'ring..

Fasteddie313 · Joined: 29 Sep 2013 Posts: 2224 Location: MI

Are you talking about the line that runs from under the intake and to the cold side of the turbo?
That is a vacuum line..

Does the car run? Does it smoke?
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80 Turbo - Slightly Modified

langmd · Joined: 30 Sep 2020 Posts: 8 Location: Minnesota

Car runs great when warmed up. Some cold start issues from vacuum leak issues I think. Smokes when starts cant really see much but can smell it. Thinking its oil in turbo burning in exhaust ??
Line with leak I'm referring to runs from airbox to small round canister then to block under intake manifold. Diagrams I'm seeing show a Y pipe after the canister with another smaller line running some where. Mine has that Y pipe n extra line deleted.

langmd · Joined: 30 Sep 2020 Posts: 8 Location: Minnesota

I am thinking from a picture on this sites technical section that my oil seepage is coming from the bottom of the Turbos built in Pop Off Valve? So could my vacuum problems lead to oil getting in there or do you think I have internal turbo issues?

langmd · Joined: 30 Sep 2020 Posts: 8 Location: Minnesota

After some continued analysis I believe the extra line I'm missing coming off the Y pipe after Purolator air oil separator is deleted because I have updated breather line running to the head which BTW has a large crack in the rubber 90°hose I have yet to replace.

Carrera RSR · Joined: 08 Jan 2010 Posts: 2194 Location: Somerset, UK

My guess is your intake system is full of condensated oil vapour from the sump building up. Its a known issue and worsened on a older/worn engine due to blow by of the rings which increases positive pressures in the sump. Even a non worn engine creates this oil mist to a more or lesser degree

Clean it all up. Fix all the oil leaks. Make sure no vacuum leaks. Compression test. Fire it up and drive.....
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1980 931 - forged pistons, Piper cam, K27/26 3257 6.10 hybrid turbo, 951 FMIC, custom intake, Mittelmotor dizzy & cam pulley, H&S exhaust, GAZ Gold, Fuch'ed, Quaife
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