AH! Bad oil leak...Rear Main Seal!?...Help!

ridelikehell · #1 (**permalink**) 09-02-2004, 11:10 AM

I stopped in my driveway while I was waiting for the garage to go up, drove in and when I walked out there was about a 6" puddle of oil on the drive...I looked under the car and I've got oil dripping down the scatter-shield on the bellhousing...
I'm guessing its either the oil pan gasket, or the rear main seal...
Is there any way to determine which it is? (or could it possibly be something else?

If it is indeed the rear main seal, I know the tranny, flywheel, clutch and pressure plate have to come out, but is that it?...I don't have to drop the crank out do I?

Thanks all!

Tony Radford · #2 (**permalink**) 09-02-2004, 12:55 PM

I've seen two types of rear main seals. One snakes over the crank from below (drop the pan) and the other looks like a donut and slips over the end of the crank after removal of the parts you listed. For the oil to be leaking at the rate you describe would indicate that either the seal is SERIOUSLY compromised or it's coming from some place else like a crack in the pan or a problem with the oil pan gasket. I lost three rear main seals (donut type) in my previous Windsor, but it was a very slow drip from the bell housing. I developed a more serious leak later on that ended up being an almost invisible hair line crack in one of the seams of my Canton oil pan. It looked like I hit one too many speed bumps.

HI Cobra · #3 (**permalink**) 09-02-2004, 01:10 PM

See how tight your oil pan bolts are - if you haven't
checked them in a while, snug up as necessary (look
for obvious cracks while you are at it) and check it
again after a drive. If you are lucky it is just a loose
oil pan, if not, the fun begins.

Clois Harlan · #4 (**permalink**) 09-02-2004, 02:25 PM

That would be a hugh rear main seal leak. I believe it is more likely something else (probably coming from your oil pan).

Regarding pulling the trans and bellhousing to pull your engine. Don't do it. Remove your bell housing bolts and leave your trans bolted to your bell housing. After removing your motor mounts and un-hooking everything you need to remove. Hook up your engine puller and put a little load on your lift. Take a large flat screw driver and pry your bellhousing away from your engine and jockey it out. Re-installing is fairly easy and way quicker than pulling everything behind the flywheel. Stabbing your engine back into your trans is much easier than it sounds.

Clois

Ron61 · #5 (**permalink**) 09-02-2004, 03:28 PM

Clois is right. That is a huge leak for a rear main. Do you have an inspection plate on the bottom of your scattershield? If so, remove it and look inside. If the leak is from the rear main, it will be wet in there. If just the outside is wet, then it is most likely leaking from another source. Also check the rear gasket of the intake and be sure it hasn't given up and let oil run down from there.

Ron

CJ428CJ · #6 (**permalink**) 09-02-2004, 05:28 PM

Don't overlook the valve cover and intake manifold gaskets. A leak at the rear of either one can run down the back of the engine and look like a pan or rear main seal leak.

ridelikehell · #7 (**permalink**) 09-02-2004, 07:11 PM

OK, an update for everyone...

I put the car up on stands and there is oil EVERYWHERE...it's ALL OVER the scatter shield, it's even as far back as the tail stock of the tranny; so why it's getting that far is beyond me...either way I pulled the little clutch fork cover off and sure enough there's oil all over that too...needless to say I picked up my new rear main seal tonight and I get to start the teardown tomorrow...

My questions now are:
- How the hell did oil get EVERYWHERE?
- and Why the hell did the thing go when I've only got 1000 miles on this engine??

Thanks for all your help so far!

Michael C Henry · #8 (**permalink**) 09-03-2004, 07:19 AM

I'm not familiar with small blocks. Do thet have one peice rear seals?A rear seal on an fe would call for removing engine just to get thr pan off.

Clois Harlan · #9 (**permalink**) 09-03-2004, 07:47 AM

If in fact it is the rear main it must have been installed improperly. That is just too much oil for a rear main. Re-check the valve covers and manifold. Also, check the oil pressure sending unit and oil filter.

If it is the rear main you may have other problems!

By the way if I remember correctly the rear seal on a 302 is a two piece rubber gasket and can be replaced with a tool that allows you to snake the gasket around the crank while everything is still in place. I tried it once and it worked out ok.

Clois

Ron61 · #10 (**permalink**) 09-03-2004, 08:21 AM

The answer to how did the oil get everywhere is simple. The wind blew it while you were driving. I have found oil as far back as on the driveline in some of my cars when I had a major leak at either the intake rear gasket or a valve cover gasket. A little oil with the wind can look like a lot more than it is. That still sounds like a lot of oil for a rear main unless the whole darn seal fell out.

Ron

trularin · #11 (**permalink**) 09-03-2004, 08:40 AM

I'll second that wind thing. Dang, had a bent front seal on a car and it virtually pumped oil out the front and srayed the guy behind me.

Completely coated the bottom of the car.

What a mess. Yes the rear main seal on a small Ford is two piece. Usually a good builder will raise one side of the seal 3/8" and make the ends not follow the cap. That is an older engine, say 1971 351.

Hope that helps.