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Oil pan gasket?

Over the last week or so I have noticed I am dripping oil on the driveway from my 98 Buick Lesabre with the 3.8 and 121,000 miles. I put the car on a lift at work today and notice all the bolts of the oil pan were wet (almost dripping) and the pan was wet. The motor above the pan seemed dry. So I am guessing oil pan gasket (PS I did check all the bolts to make sure they were all tight). I have never seen a pan gasket leak all around the pan before though, usually it’s in one spot. Could it be something else that I am missing?? It was very wet by where the motor bolts to the trans, so I am just hoping its not rear main.

Does any one know if the oil pan can just be dropped out of this Buick with out major surgery?? It seems fairly straight forward, but I want to make sure. It will be a good excuse to take a look in the pan and see if I have any sludge, that and clean the pick up screen.


After the starter is removed the pan can easily be dropped. I recall that on a few 3800 engines it was necessary to remove the exhaust manifold to get the starter out. But if a lift is available it should not require “major surgery.”

The pan is the lowest point so before throwing parts at it it would be important to rule out all leaks. In order of probability, valve cover gaskets, oil sending unit then oil pan gasket. There are other alternatives less pretty, but I would not jump to the oil pan gasket as the first response. I don’t know if you live in 1/2 inch of snow followed by an inch of salt alley, but one earlier gm car I developed a rust hole in the pan itself. Be confident of your diagnosis before throwing parts at it. Unfortunately on that rust hole pan, the engine had to be lifted or cross members removed to replace the pan.

It’s probably a lot like my 1998 Regal. You have to rotate the engine forward to get all the bolts off and drop the pan. This isn’t as bad as it sounds. You just need to detach the engine mounts to the radiator bracket and use a ratchet strap to pull the engine forward. But put it up on jack stands first and drain the oil before moving the engine.

I had a leaky pan gasket on my 3800 too. It was losing a quart every couple of weeks. It was an easy job. If there is nothing major in the way of getting the bolts undone and the pan down, its a $20 job. If its a major job, then clean everything up and have some dye added to the oil so that the leak can be detected with a black light.

Have you’ve checked for a PCV valve that isn’t functioning?

If a stuck PCV valve is preventing the crankcase from venting, the pressure in the crankcase can build where oil is pushed out thru the silcone sealant used to seal the oil pan to the block.


@Tester - That is actually my theory, when I did the intake on the car 3 months ago I apparently did not install the PVC valve correctly. As such on my first fire of the motor (about 5 min at idle not driven) It was not working right at all. I found this out when I went to open the oil fill cap and it came flying off. I belive I may have damaged the oil pan gasket at that time… Is this possible??

I agree that testing the PCV system is a first. The next is checking the rear main bearing seal. Years ago I had oil leaking from my Nissan; it appeared to be the pan gasket, but turnmed out to be the rear main bearing seal. If this is the case, it will involve some major expense.

I’m not convinced that the very temporary installation of the PCV valve backwards has anything to do with your leaky oilpan gasket. I tip my hat to your logic, however. Such an error could cause enough pressure to force seepage past the main and the cam seals, but those are rubber seals not under the same kind of compression that a good oilpan seal would be. If anything, those are the seals that would allow seepage first, and it’s not uncommon for a plugged PCV valve to force oil past the main & cam seals.

But, hey, there are no absolutes. Anything is possible.

Well the PVC system was fixed right away after I noticed the problem, so its fine. If its the rear main, well I guess I can deal with some oil in the driveway cause I am not going to put that kind of money into this car. I am still hopeing for the pan gasket, but it will be a few weeks untill I have the time to do it… THANKS GUYS

You have a polyvinylchloride (PVC) system?

(sorry. couldn;t resist the tweak. meant in good humor).