[Cosmo Mick]

Hi! I have a 1995 base bird w/3.4L and auto trans. It leaks oil. Oil comes from somewhere in between engine and tranny, leaks into flywheel cover and then leaves puddle when car is parked as the oil comes out the lil hole in the flywheel cover. It splashes back enough to coat the tranny pan. I need to add 1 qt of oil every 125-150 miles of driving. It was leaking from the day I bought the car. I brought it to my father's repair shop and he showed me that the main seal was previously done evidenced by the end of oil pain having black seal around it but claimed it was still leaking out of rear main seal. He replaced the seal, started the car up and relifted it and saw it still leaking. Told me he could not see exactly where the leak is coming from, claimed the only true way would to take the engine out due to the manner of how it sits tucked in. The guy has been doing this work for more than 50 yrs so I ASSUME he looked in all the places that he could see. It's a damn shame because the car has under 100,000 miles, about 67000 and is pretty mint other than the leak. After that, I sent the car to 9 big shops and none can find where is this leak coming from. Engine is clean on top, it does not smoke and there is no loss of coolant. Anyway, 1qt every 125-50 miles....is that considered a minor leak or a severe leak? Another person told me if the leak can not be determined, cannot be found, that these engines are prone to leaks of the LIM (I suspect passenger side but not sure). and that the best thing I can do for it is get a small block 350 and swap it out. Most advice I have gotten was that the car is not worth more than a few hundred dollars and an engine overhaul ( rebuild every single seal possible where oil can leak) will cost several thousands of dollars and that it is probably best to junk the car and move on to something else. In any case, leaking that much oil is severe or minor?

 

[GaryDoug]

Before anything drastic, you might want to try some of this stuff: http://www.amazon.com/gp/product/B0079JX4JO?psc=1&redirect=true&ref_=oh_aui_detailpage_o05_s00

It worked for me stopping a smaller rear main seal leak in my LS1. At least it put off the inevitable repair for a few years.

It seems to me that if the oil was coming from the LIM, it would not be inside the bell housing.

 

[ZumpTA]

In my opinion, that is a majorly severe leak. ...you're talking roughly 1/2 of the oil in the engine every tank of fuel. My car actually burns oil AND had a leaking rear main. ...at a rate of 1qt every several *thousand* miles. I don't know squat about the v6, but, leaky valve cover, leaky intake, or, yes, the rear main seal. Just because it has been replaced numerous times doesn't mean the the first monkey to attempt it didn't gouge something rendering a seal impossible.

While I have no love for 4 and 6cyl cars, I still disagree with the SBC opinion, for starters, you can get a complete crate motor for less than $2,300 from Sumitt Racing and it comes with a 24/36mo 50,000/100,000mi warranty. Doing a V8 swap means motor mounts, computer, wiring harness, suspension, transmission, rear-end upgrades. ...good luck doing all of that cheap AND correct. ...and where is the SBC sourced from? It certainly isn't new, freshly rebuilt, or warrantied. You're in odd spot. 4th gen birds get no love regardless of engine size, and v6 birds are a dime a dozen. ...the best move is the one you are comfortable with. ...whatever that may be.

Oh, and about mr. "I've been a mechanic for 50 years". That ain't exactly a good thing. All that says to me is "I'm set in my ways, and I'm to old to learn something new". Ask mechanics how much experience they have with your specific engine, that isnwhat counts. My dads Buick had an occational misfire that his mechanic (also a mechanic for 40 years) couldn't track down. Mechanic finally called Buick and some kid said "check the wiring harness near the exhaust manifold" ...guess what. Age means nothing, it's all about experience.

One thing I noticed with my v8 after getting the rear main seal replaced was that I was still dripping oil. Turns out my K-member collected quite a bit and that is where my current "leak" is from. eventually it'll stop.

I think I read about the v6 intake gasket leaking oil though, might want to look there.

...and it very well may be the best option to drop the engine, the entire thing, wheels, suspension, rack-and-pinion, etc just drop out the bottom as one assembly. Very little effort for a mechanic to accomplish.

 

[sea dog]

Because the main seal actually contacts the spinning crank, a groove can be worn into the crank surface. Once this happens, even a new seal won't stop the leak.

I've seen repair sleeves that fit over worn surface for the front crank seal. But I don't know if they make these for the rear seal.

Also a seal can be installed incorrectly, or damaged on installation, even if crank sealing surface is good.