ok so ive had a constant oil leak while vehicle is running ive located an area between oil pan and tranny pan between the drain plug and its up toward top of engine im thinking.... does this sound like a valve cover leak???? also how is this changed? plenum off and you have access or is there more to it??? haynes manuals for this vehicle suck and tell me nothing! anything will help thanks so much in advance

 

you are right, the haynes manuals for gen5's focus pretty heavily on 3.1's. sounds like your leak is one of 2 things, either a valve cover gasket, or possibly a head gasket. take off your oil fill cap, if the under side of the cap has some gross white stuff on it, then it is most likely your head gasket- if not, then probably a valve cover gasket. you may need to remove the upper intake, but that should be about it, on my 99 3.1- i have to remove one of the steel water lines that runs in front of the valve coveron the front and the coil packs on the back. the back one is usually the tricky one. how many miles you got on it? you think about changing the LIM gaskets while you are at it?

 

I've been wrenching on about 4-5 3100's ('94-'95) in Grand Ams (one of which I am still driving with over 200K on it).

A good portion of time you find a 3100/3400 losing oil mysteriously 90% of the time turns out to be the lower intake gaskets. I have only seen one have an oil leak at the valve cover (and it's the one I'm driving now, the plastic valve cover has a tiny crack between the edge and one of the lower bolts).

Couple of things to check for:
1 - Are you just loosing oil or also coolant?
2 - Location your EGR, use a flash light, look down along the side of it to where you can see the valley (where the intake and the block meet). If you see a LOT of oily gunk, that can be a good sign to the problem.
3 - Get a radiator pressure tester, pump up the cooling system. Listen for hissing and look around where the intake meets with the heads.

I don't work as a mechanic, but out of all these engines I've worked on for my friends/family/myself, I have not seen a failed head gasket seep oil out of the engine.

My Grand Am (longest running of the mid-90's 3100s I've messed with), had the intake gaskets changed around 90K miles, the head gaskets failed at 180K (October of '09), I tore it down, threw on new gaskets and she runs like NEW. If you have high miles on your car and find the intake gaskets need done and you plan to keep the car for a while, I'd take it down to the heads (just to give it the best shot at running reliably for a LONG time).

 

I would bet its your oil pump drive leaking. It happens to ALL 3.4 DOHCs eventually. The oil pump drive is at the back(drivers side) of the motor in the intake valley. I would shine a light down in this area:


It will be in the hole that a distributor would be in if it were an older style engine.
I bet you will see oil around that area. If it looks like the culprit, you will either need to remove the intake manifolds and rear head to replace the seal, or you can use a quick fix by unbolting the retainer that holds the drive in, lifting up on it and squirting some RTV around it to seal it back up. Its not a permanent fix, but it sure beats removing the rear head to get it out.



The oil pump drive is number 451 in this diagram and the gasket is 461. If you can get your upper intake manifold and the TB and extention off and out of the way, you should be able to get to it, tho it will be a tight fit. You cant remove the drive without removing the head because there is an ear on the head that sits over top the drive. You should have enough room tho to loosen the retainer and lift it up a bit to get some RTV around the base of it. Loosen the bolt 459 and the retainer 450 and the drive should come loose.