Oil in the Intake Manifold
#1
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Thread Starter
Oil in the Intake Manifold
Make: An early '86 32V
So I came back from the mechanic and came to some nerve-wracking news, oil in the intake....quite a bit of it too. I know a few trace amounts of oil is normal but this was maybe half a cup or so. I was able to stick my hand down the pipe where the lower part of the MAF connects behind the engine and was able to dip my fingers into a small puddle of oil.
She's got 156,000 and had irregular maintenance (was also a California desert heat car for 10 years).
My friend whose a mechanic drove her a couple days before going to the mechanic and noted she still had power. I observed a loss of power around 3-4,000 RPM and a rough starting idle but once she's warmed up, the rough idle is gone. Despite the loss of power around that range once she get's going the acceleration is quick and the top end power good.
Is the engine blown? I heard something about the PCV valve being blocked causing oil to back blow into the intake but it shouldn't be a lot.
What should I be looking for? I'm scared to think the engine is gone I was really looking forward to working on her, had a list of to-do stuff and was pre-ordering parts.
So I came back from the mechanic and came to some nerve-wracking news, oil in the intake....quite a bit of it too. I know a few trace amounts of oil is normal but this was maybe half a cup or so. I was able to stick my hand down the pipe where the lower part of the MAF connects behind the engine and was able to dip my fingers into a small puddle of oil.
She's got 156,000 and had irregular maintenance (was also a California desert heat car for 10 years).
My friend whose a mechanic drove her a couple days before going to the mechanic and noted she still had power. I observed a loss of power around 3-4,000 RPM and a rough starting idle but once she's warmed up, the rough idle is gone. Despite the loss of power around that range once she get's going the acceleration is quick and the top end power good.
Is the engine blown? I heard something about the PCV valve being blocked causing oil to back blow into the intake but it shouldn't be a lot.
What should I be looking for? I'm scared to think the engine is gone I was really looking forward to working on her, had a list of to-do stuff and was pre-ordering parts.
#2
Inventor
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Normal for quite a bit of oil in '85-'86 plenums and the MAF/TB housing (in a short time) due to the design of the 928 crank venting system.
Although it could be many things, the power loss sounds like the MAF needs rebuilding.
(MAF is likely original. Other problems could include vacuum leaks, spark plug wires, caps/rotors, etc.)
Release the flexplate, if auto, and install a PKlamp!
Although it could be many things, the power loss sounds like the MAF needs rebuilding.
(MAF is likely original. Other problems could include vacuum leaks, spark plug wires, caps/rotors, etc.)
Release the flexplate, if auto, and install a PKlamp!
#3
Rennlist Member
Thread Starter
Really? That lifts my worries a bit. My mechanic comes highly recommended and has worked on many 928s, so when he said it was engine problems my heart sank (and forgive me but for a very very small moment I almost almost thought about being a 911 convert).
The MAF does need rebuilding, I was able to take a look at it and it was in need of service. Vacuum leaks and fuel lines were also bad so he's replacing them all. Spark plugs are 5 years old but need to go. I'm getting a set of Beru wires and already ordered caps and rotors off of Roger. I considered new ignition coils too but was reading that they don't normally wear as bad as the other electrical stuff.
The MAF does need rebuilding, I was able to take a look at it and it was in need of service. Vacuum leaks and fuel lines were also bad so he's replacing them all. Spark plugs are 5 years old but need to go. I'm getting a set of Beru wires and already ordered caps and rotors off of Roger. I considered new ignition coils too but was reading that they don't normally wear as bad as the other electrical stuff.
#4
Three Wheelin'
#5
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Oil in the intake is normal.
Find yourself a new mechanic - preferably one recommended by a 928 owner. Your current one will end up costing you more in the long run.
Find yourself a new mechanic - preferably one recommended by a 928 owner. Your current one will end up costing you more in the long run.
#6
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Kevin at Injection Labs in CO will rebuild your MAF, he turns them around in a day or two. Unfortunately, all our cars eat oil through the intake ... after 20 years of evolving the 928 engine, Porsche never did figure out how to vent the crankcase without ingesting oil. The GTSs are some of the worst in this respect since the longer stroke that gave us larger displacement also increased the crankcase pressure!
#7
Man of many SIGs
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Normal but still not a good thing. Install one of these and you won't have that issue any longer. I had a major oil expulsion issue with a boosted engine. I tried the stock style louvered plate. It didn't make a difference. I installed this thing and my liquid oil ejection went away.
http://forums.pelicanparts.com/porsc...available.html
http://forums.pelicanparts.com/porsc...available.html
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#8
Rennlist Member
I have something similar on my car. No oil in my intake now. hardly any oil use also so it backs up my thoughts that my device is working.
#9
Rennlist Member
+1 on the GTS engines - I own one of those. I have heard good things about Provent setup from DR.
#11
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Thread Starter
I read up on an article by Ott's that explained the crankcase ventilation and blow back of oil problem that is inherent for the 928 engines. Now my worries are gone since it's normal
He sees and works on them regularly (was also a previous 928 owner before converting) and I remember him also saying it's the engine build when I asked about the blow back prevention so I'm confident in him. I think I got carried away a little I live in the DC Metro area and aside my own 928, have only seen one driving around so I don't know any 928 owners aside myself.
How would you go installing the scrubber and are they still available by Kuhn Performance?
Edit: I'm also planning on sending my MAF to Injection Labs for rebuild and my injectors to WitchHunter for cleaning too.
He sees and works on them regularly (was also a previous 928 owner before converting) and I remember him also saying it's the engine build when I asked about the blow back prevention so I'm confident in him. I think I got carried away a little I live in the DC Metro area and aside my own 928, have only seen one driving around so I don't know any 928 owners aside myself.
How would you go installing the scrubber and are they still available by Kuhn Performance?
Edit: I'm also planning on sending my MAF to Injection Labs for rebuild and my injectors to WitchHunter for cleaning too.
Last edited by Avar928; 03-30-2012 at 11:41 AM. Reason: + MAF
#12
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#13
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I read up on an article by Ott's that explained the crankcase ventilation and blow back of oil problem that is inherent for the 928 engines. Now my worries are gone since it's normal
He sees and works on them regularly (was also a previous 928 owner before converting) and I remember him also saying it's the engine build when I asked about the blow back prevention so I'm confident in him. I think I got carried away a little I live in the DC Metro area and aside my own 928, have only seen one driving around so I don't know any 928 owners aside myself.
How would you go installing the scrubber and are they still available by Kuhn Performance?
Edit: I'm also planning on sending my MAF to Injection Labs for rebuild and my injectors to WitchHunter for cleaning too.
He sees and works on them regularly (was also a previous 928 owner before converting) and I remember him also saying it's the engine build when I asked about the blow back prevention so I'm confident in him. I think I got carried away a little I live in the DC Metro area and aside my own 928, have only seen one driving around so I don't know any 928 owners aside myself.
How would you go installing the scrubber and are they still available by Kuhn Performance?
Edit: I'm also planning on sending my MAF to Injection Labs for rebuild and my injectors to WitchHunter for cleaning too.
Ahh welcome to the forum and welcome to the area. A few 928 people near DC.
#14
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Thread Starter
Thanks dcrasta.
If you ever see a gold 928S with a dent on both sides around Rockville (a moving truck did a hit and run when it was parked, the other dent was my dad's fault) that's me.
If you ever see a gold 928S with a dent on both sides around Rockville (a moving truck did a hit and run when it was parked, the other dent was my dad's fault) that's me.