[jhein]

Not saying this is your problem but are you sure it's the RMS? My engine when new was dry as a bone. Over time, about 5500 miles I started to get a leak at the rear of the motor. Looking at it, there was a light coating of oil over the entire back of the oil pan. I couldn't tell where it was coming from. The dripping I had was not as bad as yours but it was significant. I decided to check my oil pan bolts and sure enough, they had loosened up. So after tightening them up at my last oil change it's been totally dry.

[gtorich]

Hey thanks jhein, im pretty sure its the rear main, the whole bellhousing is oil filled when you take the inspection cover off, like i said i have oil flying all the way back to the mufflers, think i posted when i used the shop vac with one valve cover plugged and put the shop vac air on, pretty good leak from the rear seal that way.............i cant get my pan bolts any tighter................oil leak is the worse if im in the over 5 grand zone

[gtorich]

Just to add to that, so you get a better picture, i have about 1400 miles on this summer, ive put in 2qts of oil, so about 700 miles a qt, this is usually driving like a grandma, hardly hit 3 grand during shifts, just not sure if putting another seal is gonna fix this issue one way or the other.

[JLMounce]

The amount of oil you're talking about would even be significant for a rear main leak. To be that bad, I would almost suspect that the seal blew completely out, or even something like one of the oil galley bolts backing itself out.

I had a decent leak from the oil pan area that covers the rear main and it didn't spew oil everywhere.

Given that information, unfortunately I would say the engine has to come out. Spewing that much oil across the car has safety issues involved outside of just the annoyance of having to add multiple quarts of oil every 1000 miles. I would probably disassembly the entire thing and I'd be looking very carefully at the block and the crank, then depending on what careful inspection uncovers, choose to rebuild that engine or not. We've corresponded quite a bit and I know you just want to be able to enjoy this car, which unfortunately right now you're not able to.

[gtorich]

Thanks Jason, you have been a big help with all my issues. lol...........i think your right im gonna pull the motor again and hopefully fix this issue, i think it looks alot worse than it is because i drilled a few hole in the inspection cover, but it doesnt matter im gonna pull the motor again, oh boy, this is getting old at my old age, but i will do it.................hopefully i can get this thing fixed, i was hoping someone on the forum had a motor for sale that didnt leak, would be a big bonus. lol...............i appreciate all the help im getting from you guys, Jason, i take it the motor you had rebuilt is running fine...............im going to a car show on sunday, and on monday im gonna get my old ass out there and pull this thing.............lol

[mgarblik]

I very strongly recommend you smoke the engine now, while it's in the car and leaking. Remove the converter cover. Leave it just the way it is and put the smoke in the engine. Even if you have to buy a cheap smoke machine, it will pinpoint the exact location where the oil is getting out. Then you will know for sure. Had a Pontiac leak quite a bit of oil. I was 95% sure it was a rear main seal. I smoked it and not the seal at all. It was leaking at the rear main cap parting line with the block. Smoke pouring out both sides. Cleaned it up with brake clean, sealed it with RTV from the outside, fixed it. There is supposed to be sealer between that rear cap and the block but lots of builders forget to do it. It's in every service manual. Had another one that filled the converter cover with oil and the leak was the back of one valve cover!. The oil came out, ran down the back of the block, filled up the converter cover and the converter threw it all over the floor of the car. A smoke test eliminates the guessing. Good luck with it, hope you find the problem.

[gtorich]

Mike, i hear you loud and clear on the smoke machine, they did that at the shop where i had the motor done, they put enough silicone on the front of the oil pan, they said that was the leak, dont know sure of that deal...............for Jason here is a pic of a 15 mile run, as usual hardly anything just the two spots, when going 100 miles a different story, thats for sure.......i cant believe im having all these issues with this motor, thing runs perfect, well except for the small/big leaks. lol

Rich

[PontiacHO]

A wide thrust clearance can also cause a bad RMS leak. The crank “walking” back and forth ruins any seal. A new seal wouldn’t last anytime. Some engines were knocking with all that clearance. Replaced crankshafts under warranty in the late seventies at the Chevy dealer. Nothing was machined consistent back in those days.

[PAUL K]

When all else fails find an original GM asbestos rope seal

[Sirrotica]

Rich, just a quick suggestion would to be to call, or E Mail Wade at BOP. He designed the BOP seals and probably has as much knowledge as anyone walking the face of the earth about rear main seal failures, and what to look for as far as defects in your current block/bottom end.

Mike Garblik is a huge proponent of smoke machines to find fluid leaks, they've come down in price so that the DIY guy could afford a basic one.

Maybe Wade will have something to look for as far a the knurling on the crank, or there is always a possibility of a porous block casting.

While working at a buick dealership many years ago I had a V6 buick that seeped water and oil near the rear main seal, turns out that after myself getting fired (and rehired a day later) over not being able to seal the engine up, the problem was tiny pinholes in the casting, requiring a new shortblock. After many repeated rear mains (done for free by me due to flat rate system) and attempts to find a leaking soft plug, I wasn't the problem. BTW all the attempts were done with engine in chassis, after removing the engine from the car we finally identified the porosity problem.

If this is your case, the smoke machine may assist you if finding the problem. Good luck in whatever avenue you decide to follow, I'm 72 currently and can identify with diminishing physical abilities due to age, and attitude.

[grivera]

I have this one - at this price it’s a no-brainer:

https://a.co/d/0nDn6AU

[NeighborsComplaint]

Originally Posted by gtorich

Mike, i hear you loud and clear on the smoke machine, they did that at the shop where i had the motor done, they put enough silicone on the front of the oil pan, they said that was the leak, dont know sure of that deal...............for Jason here is a pic of a 15 mile run, as usual hardly anything just the two spots, when going 100 miles a different story, thats for sure.......i cant believe im having all these issues with this motor, thing runs perfect, well except for the small/big leaks. lol

Rich

Those 2 small drips? Hardly anything to get excited about. If it was a rear main, it would drip straight down on the centerline of the crankshfft and along the oil pan rails wiyh drips at the bolt locations.

It looks to me like the rear main cap was not set in silicone or the silicone bead wasn't carried all the way to the edge of the cap.

[HWYSTR455]

I went thru struggling with RMS leaks, and in 3 cases, it turned out to be the pan leaking at the main cap gasket.

During a few of those instances, I went back to a rope seal, the 'grey' ones, maybe those are the 'Best' seals? Anyway, had the rope seal install down to an art, and never had a leak after. From the RMS anyway. And it takes a few times with the crank test fitting and checking, making sure there isn't too much drag.

The pan leaks were frustrating, and found the cork seal was the best to use on the cap area. In some cases it depends on the pan, but in general, I found even on some of the pans that had the grooves/holes for the rubber seals, the cork still worked the best.

The rubber ones squirm, shrink/balloon, and never worked right for me.

You do have to work the cork ones tho, test fit, trim, test fit, etc. Also would glue it to the cap with RTV, and just set the pan on it to hold it in place as it setup/dried.

Pan rail gaskets you have to be selective of too, but think I used to use the Fel-Pro fiber ones which were kind of thick. They were black as I remember. Think I have the part number somewhere.

I use studs on the pan rails now exclusively. Gluing the gasket down with them is cake, and they won't walk when putting the pan on. And yes, after a few heat cycles you should retighten.


.

[vertigto]

Good info right there ^^^^^^

[Dragncar]

Those rubber rear main gaskets are a waste of time. I wanted to use a big piece of 1/4" cork like Cliff does but I was having a hard time finding it.
What you can do though is buy 2 cork gasket sets and use 2 of the cork rear cap gaskets side by side. Thats what I did, there was enough room to do it. I used the yellow gorilla snot trim weatherstrip adhesive stuff under the cork between the gasket and cap. Bolted the pan down overnight to set the glue and used grey silicone on the other side for final install. No leaks which on a Pontiac is a accomplishment in itself.

[gtorich]

Originally Posted by NeighborsComplaint

Those 2 small drips? Hardly anything to get excited about. If it was a rear main, it would drip straight down on the centerline of the crankshfft and along the oil pan rails wiyh drips at the bolt locations.

It looks to me like the rear main cap was not set in silicone or the silicone bead wasn't carried all the way to the edge of the cap.

Think i got some pics mixed up, check out post 20, thats a little more than the two small drops i had posted.......this was driving the car never going over 3 grand on shifts, if i got into the high 5 grand, it was worse, got the motor out now and hoping to find out what is going on with this thing.

Rich

[gtorich]

Originally Posted by HWYSTR455

I went thru struggling with RMS leaks, and in 3 cases, it turned out to be the pan leaking at the main cap gasket.

During a few of those instances, I went back to a rope seal, the 'grey' ones, maybe those are the 'Best' seals? Anyway, had the rope seal install down to an art, and never had a leak after. From the RMS anyway. And it takes a few times with the crank test fitting and checking, making sure there isn't too much drag.

The pan leaks were frustrating, and found the cork seal was the best to use on the cap area. In some cases it depends on the pan, but in general, I found even on some of the pans that had the grooves/holes for the rubber seals, the cork still worked the best.

The rubber ones squirm, shrink/balloon, and never worked right for me.

You do have to work the cork ones tho, test fit, trim, test fit, etc. Also would glue it to the cap with RTV, and just set the pan on it to hold it in place as it setup/dried.

Pan rail gaskets you have to be selective of too, but think I used to use the Fel-Pro fiber ones which were kind of thick. They were black as I remember. Think I have the part number somewhere.

I use studs on the pan rails now exclusively. Gluing the gasket down with them is cake, and they won't walk when putting the pan on. And yes, after a few heat cycles you should retighten.


.

Hey thanks for that info, i used the one piece oil pan gasket from bop, should have cut the rubber ends off and used a cork piece over the main cap which i had but didnt use..........i guess really dumb question when taking the motor apart can they tell what was leaking, oil pan or rms, right now i have the flywheel off, cant see anything that might be leaking, im in the process of picking up a smoke machine . All good points from you guys, i just dont feel confident with this motor anymore, not sure what to do there.............also on using studs, how do you retighten after a couple heat cycles, hard to even see some of the bolts to tighten them down.

[gtorich]

Originally Posted by Dragncar

Those rubber rear main gaskets are a waste of time. I wanted to use a big piece of 1/4" cork like Cliff does but I was having a hard time finding it.
What you can do though is buy 2 cork gasket sets and use 2 of the cork rear cap gaskets side by side. Thats what I did, there was enough room to do it. I used the yellow gorilla snot trim weatherstrip adhesive stuff under the cork between the gasket and cap. Bolted the pan down overnight to set the glue and used grey silicone on the other side for final install. No leaks which on a Pontiac is a accomplishment in itself.

Hey, Dragncar, missed this while typing , i got cork gasket from butler, will have to measure it, if not a 1/4 inch i will get what you did...........what did you use for the rest of the pan.

Rich

[JLMounce]

Originally Posted by gtorich

Hey thanks for that info, i used the one piece oil pan gasket from bop, should have cut the rubber ends off and used a cork piece over the main cap which i had but didnt use..........i guess really dumb question when taking the motor apart can they tell what was leaking, oil pan or rms, right now i have the flywheel off, cant see anything that might be leaking, im in the process of picking up a smoke machine . All good points from you guys, i just dont feel confident with this motor anymore, not sure what to do there.............also on using studs, how do you retighten after a couple heat cycles, hard to even see some of the bolts to tighten them down.

So you're not seeing anything in the back of the engine that's leaking after removing the flywheel?

Is it possible the leak has been coming from the back of the valve covers? I can't recall, but believe you run an aftermarket head correct? Some of these don't return oil as quickly as the factory heads and in periods of high, or sustained rpm use, you may find that you've got a puddle of oil in the back corner of the head that is above the gasket line.

In that case, you can get drips down the back of the head that will pool around the bell housing area. You'll likely also notice it on the starters.

Is the back of the heads wet? What about the starter?

[gtorich]

Originally Posted by JLMounce

So you're not seeing anything in the back of the engine that's leaking after removing the flywheel?

Is it possible the leak has been coming from the back of the valve covers? I can't recall, but believe you run an aftermarket head correct? Some of these don't return oil as quickly as the factory heads and in periods of high, or sustained rpm use, you may find that you've got a puddle of oil in the back corner of the head that is above the gasket line.

In that case, you can get drips down the back of the head that will pool around the bell housing area. You'll likely also notice it on the starters.

Is the back of the heads wet? What about the starter?

Jason, how are you doing........nothing on back of the valve covers, i do have the kre heads, nothing looks wet there, most of the oil pooling in inside the bell housing , once the inspection cover get full of oil its leaking on the starter not to mention all the way to the rear of the car, weird part doesnt look like anything oil wise is on the flywheel, but that is probably flying off, motor is out now, hopefully someone can figure this out. I will see if i can post a pic for you later of the back of the block, i have it on a engine cart now.

Rich