I have an oil leak that is causing the bottom of my transmission and rear driver side block to get covered in oil. Looks to be coming from around where the bottom driver side intake manifold bolts into the head. No leaks from the valve cover, starts lower. Any idea where this could be coming from?

Oil pressure sensor perhaps.

Also check around the rear driver side where your headgasket is. I think 420a's have a problem with the cylinder head and block seperating there due to the head bolt bore not being quite as deep as the rest. Is there any oil in your coolant?

If you are seeing oil collecting on the bottom of the tranny, I would say it is one of the following:

OPSU
Internal tranny leak at the input shaft seal/bearing
Rear main seal
HG

Good luck!

I checked the coolant the other day and it is clear as the day I put it in; so no oil in it.

It looks to be above the tranny plus doesn't the tranny only hold transmission fluid? This is definitely oil and not tran fluid.

I will try to take another look for OPSU and oil pressure sensor. Still trying to find where the rear main seal is located and check that too.

Thanks.

Do you have an axle boot tear? That will fling crap everywhere.

I say Head Gasket.....that's what mine was at around 48,000 miles.

If you are seeing wetness above the tranny that I would have to say it is either the HG or a leake from the head. If the VC gasket is not leaking, you still could be getting leakage from the half moon shaped cam cap. I had issues with that in the past.

I've inspected all around the valve cover and the half moon. No signs of oil. If head gasket, wouldn't I be getting oil in coolant or vice-versa?

Originally posted by Eric
I've inspected all around the valve cover and the half moon. No signs of oil. If head gasket, wouldn't I be getting oil in coolant or vice-versa?

Not necessarily. You could easily lose quarts of oil out the back side of the block without naving transferance. Hell you could keep goin like that for quite a while (of course peeing all over the road and everybody else's driveway).

But I'm leaning toward checking that OPSU. Did you?

All I can see on the back of the block is caked on oil. The only place it has a drip of oil is the bottom of the tranny. My car is parked in the garage and I only get a few drops of oil on the floor from where it drips off the tranny.

I cleaned the back of the block off with brake cleaner. Ran the car for awhile and revved it up a few times. Couldn't find oil coming out of anywhere.

Will need to just randomly check it once in awhile to see if I can spot the source.

I will go with OPSU too Eric.

Also, for the headgasket guys MB is right. I had a HG blow - never had oil and coolant mix.

One morning all hell broke loose and I lost it all within a minute.

And dont forget about the good old rear main seal. If that leaks, oil gets introduced into the tranny and when it hits the flywheel/flexplate it will shoot all over the damn place.

OPSU is a good, easy, cheap thing to replace though. Might as well start there and at least narrow things down a little.

Doesn't seem to be the OPSU. Think it's the rear main seal. My clutch just started slipping the other day. Do you think oil would be getting in there and causing this or just an opportunity to replace both?