Oil In Intake Manifold.....Any Ideas On How It Got There???

[jmciver]

I was finishing up my nitrous install when I decided to get rid of the temp sensor and coolant hoses from the throttle body (they were really getting in the way). In order to get the hoses off of the throttle body, I had to pull the throttle body off of the intake manifold. When I removed the throttle body, I noticed what appeared to be some oil just inside the intake manifold. Now my gut is telling my that there should not be any oil, or any type of liquid for that matter, inside the intake manifold. But then, I am no BMW master mechanic either. Can someone give me some insight into this?? Thanks!! And BTW, the car appears to be running fine and strong as ever....

[bmwpower]

This is common. Some oil (more like residue) is okay, a lot of oil is not okay.

[MauiM3Mania]

Do we have some sort of crankcase evacuation into the intake system?

Scott

[moonluv810]

Dunno if this is possible. If you have a K&N type of filter and probably put too much oil on it???? Just an idea.

[jmciver]

Originally posted by moonluv810
Dunno if this is possible. If you have a K&N type of filter and probably put too much oil on it???? Just an idea.

Actually, I have seen that, but it was on the elbow of the rubber boot. The stuff I saw was definately oil. But it wasn't that much, only a bit of residue. I think bmwpower is probably right since it is such a small amount. Thanks for the insight.

[98///M-DROPTOP]

Not sure how a 95 is hooked up but for 3.0L and 3.2L there is a hose that comes off of the Vanos cover that draws off crankcase gases and cycles them through the intake but it's difficult to see how this connects up in the ETK for a 95. On 96+ 3.2L, this hose connects to a device described as a "pressure regulating valve".....aka PCV I think, and then into the intake and possibly back into the oiling system. The group diagram that depicts this is titled "CRANK CASE - VENTILATION/OIL SEPARATOR" but from experience I've also seen an oil film and small puddle inside of the intake plenum so I wonder how effective it really is.

[BSH]

It's normal to have oil in the intake plenum. Excess oil is drained to the crankcase via a tube. Don't worry about the oil.

[heatmizr]

this is common on bikes i know... i would assume the same on cars.
its an emmissions thing, to send unburnt blow-by gases from the crankcase back thru the intake to burn 'em up.