I've got the transmission out of the car. The radiator is coming out tonight to get a hole fixed in it. I've got a leaky rear main seal that I must have screwed up last year when I resealed the motor. So I'm thinking just pulling the grill and the hood and picking the whole thing out of the car and onto the engine stand. Now, I don't want to this again for a LONG ass time. Someone please give me the definitive end all procedure for installing the rear main seal in this 390. I'll be using the modern FelPro 4 piece seal kit.
In my opinion, it's hard to seal up the FE fords. I've had a few of them, and they all seeped or leaked! When we (my uncle, and I) put my 390 together about 18 months ago we just followed the FelPro instructions. My rear main does seep a little, as well as the valve covers. It's not nearly enough leakage for me to worry. I guess it all depends on what is acceptable to you. I go 3,000 miles between oil changes and it's not even a pint low at 3,000 miles. Not too bad, I think. This might not help you much, but I just had to add my $.02! Malcolm
Check the main bearing clearamce, if it's much over .001, put in a one under main. Thats the biggest reason the seal leaks.
Dano, Do you run a PCV or is the crank case vented to the atmosphere? You would be supprised how much a correctly set up PCV system will help your leaks. Brick
While it's certainly possible you have a leaking rear main seal, it's more common for the joint where the intake/head/block meet to leak down the back of the block making it look like the seal. Before you yank the motor, go to Napa, buy some brake clean and a bottle of leak dye to put in the crankcase. Thoroughly clean the back of the block, heads, manifold, and bellhousing with the brake clean then put the dye in. Drive it around for a while then go dig out the storage box that's up in the attic (you're looking for the black light next to that grungy old bong you hid from your parents). Pop the hood at night, put the blacklight in the engine compartment, and the leak (and the trail) will glow showing you exactly where the leak is. Don't be surprised if it's the manifold or even a valve cover gasket. Worse case is that it IS the seal, and you wasted a couple days, and a few bucks on dye and brake clean. If it's NOT, you've saved a TON of time and headache.
Alright, I did some investigating tonight with some suggestions from you all. A buddy suggested also that if my trans was covered in oil on the top of the bellhousing that it might an intake or valve cover leak. Sure enough, the trans was pretty drenched when I removed it and the leak was way up high. The flex plate and also every part of the crank sticking out the back of the motor, even way up on the oil pan side, was completely dry. Looking at the back of the block from under the car where the trans was I can see the passenger side valve cover gasket seeping pretty bad. Also the oil fill tube on the front passenger side was pretty wet with a track of oil on the top side of the valve cover. The rear part of the intake gasket was wet, even a little wet with antifreeze as was the rear of the driver side valve cover. All that conveniently dripped its way back down the rear of the motor and looked like a rear main leak. So, given this new info I think an intake and valve cover gasket change should fix most of the leak, or at least enough to see if the rear is actually leaking at all. With all the other stuff I have to do before Bonneville I'm almost glad to not add a rear main seal to the list. Oh, and Brick -- I checked out the PCV valve as you suggested. Wouldn't you know, it was pretty gummed up. The valve would barely move and the bypass in the valve was gummed shut. According to my Ford manual that means that at a high vacuum condition of the motor there was no crankcase ventilation. The metal unit was rebuildable, so I opened it up and cleaned it all out, then checked it with an airline. Works awesome now, so hopefully that will help and solve my problem with my filler tube puking oil all over the passenger side of the intake and valve cover. I'd still like to see some suggestions from other on doing that 4 piece rear main, so chime in if you have some suggestions on that.
My 390 had a rear main leak (new rebuild) replaced the seal still leaked. My wife was useing as a dailey. She didn't use the Tri-Power much and the outside carbs leaked so much it filled the pan with gas. After changing oil twice in a row it has never leaked. Guess the gas swelled up the seal......OLDBEET
Is this the common joint leak you're speaking about? I can't figure out where its coming from but oil beads up right at that T intersection.
Might be an old thread, but people seem to have problems with it! I just follow the instructions on the seal kit and have no problems with my FEs. Like said also make sure you seal the intake properly, everyone has their ways, I know I have mine! Likewise on the valve covers and you will have a oil tight FE. All of mine have never leaked anywhere. Just like my dusty Shovelhead engine! Bones
That is one place where you need a little extra sealer, also at the top of the main. I coat the entire area where the main goes with a THIN layer of sealer. I also coat the side seals and cap groove. Use the sealer of your choice, there are lots of good ones out there. Also check the intake and valve covers. There proper procedures for sealing them too. They sometimes cause problems that look like bad main seals. Bones
I have an FE in an OT truck that leaks right under rear main area...this has me now wondering if it's something a bit higher up. For now, it just gets parked in the gravel
On my old panel I used the nails first, then it leaked, after MUCH reading I ended up cleaning it all out, cleaning all the parts and using the Right Stuff. After everything is clean and dry, use the long tip and start filling. I used a real nail to pack it in, when it starts coming out the sides it's full. Let it fully dry and run it, mine didn't leak again and I owned it a few years longer.
Thank you Bones! Alright so this might be a dumb question but if it's leaking from that intersection point do you think its likely the pan/gasket. Versus if its leaking from below the crank it would definitely be the main seal correct? The engine is out of the car and separated from the transmission. I'm guessing the best thing to do now is to get it on a stand, pull my pan back off, and start from there? Many thanks you guys
Yes, oil leaks are a bitch! They can puddle here, but actually be leaking there. The best way to find a leak, if you can is to clean/dry the whole area, then run the engine and test the area with white paper towels. That way you usually find the source, but underline the word usually! I spent a life time chasing oil leaks on gas and diesel fire engines. Seems like the firemen don’t like oil on their floors! It can and will fool you. Sometimes you just can’t do what you need to do. Since you have the engine on a stand, pull the pan and replace the main seal, both on the crank and the main cap walls, properly. Then you have no worries, $40 a couple hours, a couple of beers and your golden! Bones
That does sound like a pretty solid guarantee. That is of course as long as I can follow the directions! Attempting to rebuild my carb tomorrow night so I'll save this gem for later in the week. Thanks for the advice!
We all Know FE intakes are heavy to install I have had the best luck by making two studs about 6 to 8 inches long. Install them in the intake bolt holes in the front and back of one head use them as a guide and slide the intake down and over the end rail seals will stay in place.
My car has 200 six with the rope seal. Over the winter it seaps a little, but as soon as I start driving it every day or so it quits. I think it might be the nature of the rope seal.
One thing I have noticed over the years, is the intake gasket on FE's like to give up at the rear after 30 to 40 years, and will certainly make one think that the rear main seal is leaking. Not to get too far off-topic, but I like to use the rubber seals that come with the intake gaskets, instead of silicone. Glue them in place, let them sit for a day, then install the manifold as Sunbeam suggests above, using a dab of sealer at the corners. I like to use cutoff bolts with a screwdriver slot cut in them so I can get them out without jockeying the 80 pound intake around.
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