[V6-12v] Oil leak under intake manifold

[apowell at colocougs.org]

Jon Hohlfeld <jonhohlf at yahoo.com> said:

I have been experiencing an oil leak for a while in my 94 90 quattro, I have been noticing burnt oil
smell when I stop at stop lights. I was checking into it today and it appears there is oil pooled
under the intake manifold, and that it is running down the back of the engine and onto the exhaust.

My question would be for someone who has experienced this, what gaskets should I have on hand when I
dive into it, and what would be the best source for those gaskets? I don't want the car to be out of
commission too long, as it is usually the car my wife drives and the one with the car seat in it.

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Jon, I've recently been through this with a 1993 90Q V6, and others on the list were kind enough to
help me - I'll pass along the favor.

The V6 motors from this time period live long, healthy lives but also are prone to multiple problems
with oil leaks.  In increasing order of severity (read: time and expense) they run about like this:

1) Valve cover gaskets
2) Rear cam seals
3) Valley pan gasket (under intake manifold)
4) Rear main seal
5) Head gaskets

I won the prize and ended up with #5, worth about $1000-$1500 in labor and parts at an independent
shop - and although I usually do my own car work, I decided this was one I didn't have the time for.
So I paid the man.

But...HERE'S THE KEEPER. HERE'S HOW TO FIND OUT IF IT'S A HEAD GASKET LEAK.

I finally spoke with a gent who had done a lot of work on these, and the single most common place
for the head gasket to leak is on the driver's side, about 1/3 of the way back from the front. It's
under the intake manifold, BUT - if you get a small flashlight, aim it back through the manifold and
watch carefully while you rev the engine to 2500 RPM or so, you may see a small trickle of oil
running down the block at that point. Once I saw that trickle, I knew it was the head gasket. Turns
out there's an oil passage very, very close to the edge of the gasket and the seal just fails
sometimes. Q@#6$)$&!!!

If that is what you see, you're in for a set of head gaskets. While you're at it, of course you want
to do the valley pan gasket, cam seals and valve cover gaskets. You may also want to put new valve
stem seals in. Be ready for the exhaust manifold studs to be stuck and require lengthy heating to
get the studs out without breaking them off. While you're in there, have a machine shop check the
heads to make sure they're perfectly flat and if not, have them milled slightly.

I hope for your sake that this is not the problem, and that it's something more basic. Never in 38
years of driving many, many cars had I ever had a head gasket leak oil before, but this one did.

If you do this as a DIY job, please read the intake manifold removal procedure at
http://www.12v.org/maintenance/repairs/headgasket.php

For helpful hints.

************************************
Al Powell
apowell at gocougs.wsu.edu
1958 Fiat 1200 Transformabile Spyder
1983 Datsun 280ZX Turbo
1993 Audi 90Q
1991 Camaro RS Convertible
1997 Chebby Blazer
1999 Chebby Blazer
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