I recently purchased a 1994 Caprice which hasn't moved in a year. It was at an auction and never leaked oil. I started the car and it runs great except for the fact that it's leaking oil. I see its collecting in the flywheel cover. I haven't got it in the air yet but could it be a rear main seal or what? Also if it is how's the job of dropping the trans and gettin er' done?

i'd say 80% chance it's the rear main.

I recently purchased a 1994 Caprice which hasn't moved in a year. It was at an auction and never leaked oil. I started the car and it runs great except for the fact that it's leaking oil. I see its collecting in the flywheel cover. I haven't got it in the air yet but could it be a rear main seal or what? Also if it is how's the job of dropping the trans and gettin er' done?

It could be the rear main seal, it could also be a leaking valve cover, intake rear seal, or distributor gasket. Clean the engine real good, use a high-pressure hose for this, and then drive it for a bit and see were the new oil is.

If you have to change the seal. I think if you pull the distributor remove the bolts in the engine mount you can remove the oil pan by jacking up the engine. Loosen the crank bolts and you can install a neopreme seal. Then retorque the bolts. Clean the oil pump strainer before reassembly. Take some white out and mark the rotor and a mark on the side of the distributor. Don't turn the crank shaft this will make it easier to reinstall. I always use no.2 permatex as silicone makes it to easy to break pan bolts unless you clean out all the bolt holes with a small screwdriver.
Make sure you check the thrust bearing by using a big screwdriver to check end play. Also check a crank and connecting rod bearing while you are doing the work.
You should be able to do all of this on a day off from work.
I made a mistake I was thinking my 79 Impala was an 89 Impala.

No need to remove the distributor, since it's mounted to the front of the engine on a '94 (OptiSpark).

However, the transmisson and torque converter need to be removed, since the rear main is a one-piece design on 1986-up SBC engines, including his L99 or LT1. No need to remove the oil pan, just the seal carrier.

There is a chance that the rear crank seal has dried, and might be able to be "saved" by using synthetic lubricant instead of mineral oil in the engine. There is a chance that the leak is actually from the rear intake "China Wall" or valve cover, or the oil pressire switch, and a small chance that it is from a rear plug in one of the lifter oil galleries.

No need to remove the distributor, since it's mounted to the front of the engine on a '94 (OptiSpark).

Sil Slaps his own head ... :eek7: :eek:

Just grab another cup of your favorite caffineated beverage. Been there...

That's O.K. Look at me - I can't manage to spell "pressure" correctly. Poor old Fonz is going to spend a lot of time looking for that "oil pressire" switch. ;)

There is also a chance that the leak could be at the pan gasket, and oil is wicking along the trans inspection cover. Then there is the possibility of the 'O" ring leaking at the oil cooler/filter adapter, allowing the oil to wick back to the flywheel cover. That's a common leak.

Wherever it is, Silicon's suggeston for cleaning the engine is a good one.

ok sounds good what kind of oil and or additive should i use?

It would be good to follow silicon's advice and clean up the area first, then try to locate the leak.

If it were mine, I'd use a fully synthetic PAO lubricant (NOT a Group 3 "synthetic" like some companies try to pass off as a true synthetic). I've converted to synthetic on engines with well over 100K miles with no problems. Be aware that some leaks that are masked by sludge may become more apparent as the synthetic cleans the sludge away. These may eventually improve as the seal conditioning of synthetics slowly restores the elasticity of the seals. It didn't start to leak overnight, and it won't get better overnight, short of disassembly and replacement of seals and gaskets.

Just grab another cup of your favorite caffineated beverage. Been there...

That's O.K. Look at me - I can't manage to spell "pressure" correctly. Poor old Fonz is going to spend a lot of time looking for that "oil pressire" switch. ;)

There is also a chance that the leak could be at the pan gasket, and oil is wicking along the trans inspection cover. Then there is the possibility of the 'O" ring leaking at the oil cooler/filter adapter, allowing the oil to wick back to the flywheel cover. That's a common leak.

Wherever it is, Silicon's suggeston for cleaning the engine is a good one. Thanks! Thats exactly what it is! the oil filter adapter leaking. Where can i purchase the o ring at? The part store acted as if I was speaking a different language.

Go visit the General. Any dealership parts department should have the ring in stock for $2-3 at most, P/N 10244495.

Thanks! Thats exactly what it is! the oil filter adapter leaking.

From what I've heard, that seems to be a fairly common problem. Mine leaks just a little bit (a couple of drops after sitting a week) from that oil filter adapter. My question is, does it involve any major work to replace?

If you're one of those rare few people who classify getting up in the morning or bending over to tie shoes "major work" then it might qualify. The rest of us would probably classify it as an easy fix, and a good excuse to change the oil.