Oil Leak

I've read other threads about oil leaks on ~'95 gp GTPs with the 3.4. and mine is doing the same, about 2 quarts between oil changes. and i know it has to be either the oil pump seal where it would be on the 3.1 or the oil pan gasket. (more than likely the oil pump seal) but...i've noticed where it leaks from and it is all over the transmission pan and oil pan, which made me think it was the oil pan gasket. So i thought i was gunna be able to change the gasket no problem like most cars, but NOOO i find out its like a $250 dollar job at a shop because all the stuff in the way. :mad: Is this really true??? :confused: but anyway, from those symptoms of the oil all over the transmission pan, what would ya'll think would be the more likely problem, oil pump seal, or oil pan gasket?

Two quarts is a lot between changes for an oil pan gasket, unless it's completely given way. You could have a leaking rear main oil seal. What does your driveway look like--any big oil stains??

yea, It leaves an area about 8 inches wide lightly wet....

Well, you've got yourself a good sized leak. Recommend you degrease the affected area as much as possible and watch it over a period of a couple of days to try to narrow it down. But it make take a dye test to really diagnose it. My best guess is the rear main.

more than likely the oil pump seal

The oil pump is Located at the front of the engine by the belt's.Sound's like pan and rear main seal....have you tried to tighten the oil pan bolt's ? Might get lucky and help some of the leak that way.Also to check and see if the rear main seal is bad,remove that plastic inspection cover on the tranny and see if you have oil in the bottom of cover.


~Larry~

i will check the oil pan bolts (hopefully it is just that) and i'll try to take that plastic cover off to see if that is the problem. How much will it run me to repair that rear main seal?

i will check the oil pan bolts (hopefully it is just that) and i'll try to take that plastic cover off to see if that is the problem. How much will it run me to repair that rear main seal?

alot,because the tranny has to be moved out to get a 5 doaller seal in the backside of the motor...Last I herad for a 97/03 it was about 900 bucks for labor.

!!! id never pay that. The whole car was only 1500. I hope it will help enough by just tightening the oil pan bolts, lol.

It cost $1472 to have my rear main and oil pan gaskets (includes a new oil pan too) done. Glad it was under warranty at the time.

this is the 3.4dohc if i am not mistaken. one thing i have learned tried and true. is that the oil leak, isnt necessarily coming from the first thing that is wet. look to the farthest forward and uppermost part of the leak. i had that motor in a 92gp that i had. i had a leak on the back of the motor that costed me $740 i dont recall if it was the back valve cover or what. but i know it wasnt the pan gasket. could be an oil sender unit or level sensor. check the little things first. and trace it as far forward and top most, gravity and driving it make it move down and back. some mechanics will put a dye in your oil to trace where it is leaking. happy hunting. and good luck.

Hi TW,
It's me again!!!
Yes, we had this problem too. Same symptons: oil all over the tranny case and likely the cross member below--it even soaked the starter?

I was told (by the same trusted coworker) that these engines have a distributor plug which sits at what is the rear top of the engine (typical of a GM engine). Since these cars do not have a distributor or a distributor shaft, GM plugged the hole with a rubber plug which is notorious for failure and then that allows the oil to be pushed out that opening--he explained that there is some kind of drive shaft in there--maybe for the the oil pump(?) which makes this spot like a "Carotid artery" of the engine--when it leaks, you lose plenty. In our case, it turned out to be the intake manifold gasket with the leak in the same area, very hard to see. You have to look at the back of the engine. In the case of a transverse engine, this is the drivers side of the engine compartment. In our 3100, this location is found by looking near the brake master cylinder reservoir and look down there at the engine--you will see the location where the distributor would have been installed. It is very easy to see an oil leak. The oil "washes" the area showing itself clearly. One like this should be easy to find, I would think. Good Luck--It should be fixed. We had a shop do the intake--it is far too much work for this novice.

John R

I wish it was just my intake, cuz ive replaced the lower and upper intake gaskets on my engine (3.4) and my moms (3.1) lol. but i have a bad feeling it is that dreadful oil pump seal. ...To tell ya the truth, changin the intake on the 3.1 is super easy, but it was quite a pain on my 3.4 lol. Thanks again for ur posts.

Mine leaks about 2 quarts between changes as well...

yes, i know of that oil leak, as i have fixed many, in fact would have been my first post, seeing how it is the most common 3.1l/3100 leak there is. i believe it is call the distributor plug car oring. or some name like that. but in your first post you mentioned having a 3.4 which in that year is not the same block i believe. however. i am glad to hear you got it fixed.