Oil inside intake manifold. Sludge everywhere..

[Da Coupe]

Hey all,
I have my 98 motor (150k) on the stand right now and pulled off the intake manifold. I noticed a lot of oil sludge in all the intake ports of the head (enough to scrape off with a spoon) so I decided to separate the intake in half to try and track down the culprit. To my surprise I see oil sitting on the bottom of the lower half manifold. Enough to swish around. The entire gasket is soaked in oil also. Is this normal?? 98's don't have an egr so could it be a faulty pvc? Is there anything I can eliminate off the motor to prevent this? Maybe install a catch can? Could blowby actually cause this? I want everything running perfect before I throw this baby back in. Hoping to avoid rebuilding if I don't have to. Any thoughts?

 

[gloverman]

Is it a VVti engine? If it is every one I have worked on is has oil in the manifold , Just like the 3S-ge beams motors.

 

[Da Coupe]

Yes it's a vvti motor. So what's the reason for the oil accumulation? Is there a way to prevent this?

 

[gloverman]

I beleive it is from normal engine operation and the manifold design. It seems to be happen in engines where the manifold has a low point where the oil can collect. I also see it alot in Euros like BMW and Audi. These also have similar manifold designs. Its not really causing a problem so I haven't looked into preventing it. Possibly adding an ugly catch can in series between the PCV valve and manifold may help. I would not suggest removing the PCV valve as they make a more efficent engine.

 

[Da Coupe]

Hmm.. even if this is normal it still bugs me. I guess I'll just clean everything up and install an ugly catch can. I appreciate your input. Thanks

 

[George_R]

gloverman, but won't the manifold oil build up carbon on pistons, valves etc? With possible derating of oil rings, knocking issues and so on?