[25stevem]

In regards to the above post, what do you mean by something more reliable and a engine swap?

Are you thinking about switch over to something other then a Pontiac just due to a rear main leak?

These days with the choices that Pontiacs have for seals if you can’t get one of these to not leak on you, then it’s not the seals fault, it’s a installation issue!

[AG]

That post is spam.

[67Fbird]

Originally Posted by shaker455

One piece works great and i've had good luck....I
I usually do a tilt test with an engine crane to test the seal for leaks.

Thankyou for that TIP...

[67Fbird]

Originally Posted by Cliff R

I agree to verify that it actually is the seal and not the pan or something else.

Using lip-type seals on factory cranks is hit and miss. Factory cranks have serrations cut in them to help the rope seals work correctly. Sometimes they are cut pretty deep and if the lip seal lines right up on them they will leak every single time.

I always do a mock-up with a lip type seal before deciding whether to use a rope seal instead. For most engines I've done with factory cranks I've used the Best rope seal and never had one drop of oil get by one. For aftermarket cranks I always use the Viton two piece seals (custom fitting required), and never had a leak with one of those to date either.......Cliff

Maybe I got lucky....but I installed a 1 pc BOP on my new eagle crank and I could NOT find anything I could/would do to make it fit any easier than it did. Only tip i can give is be gently when you twist it to get it on the crank..

[78w72]

Originally Posted by steve25

Your going to atleast need to drop the trans off and flexplate, then spray out the whole seal area with Carb cleaner to dry it out and then really jack up the nose of the car and remove the oil filler cap.
Then you will likley see where the oil is really seapping from.

Hopefully is from around the OD of the seal or the pan gasket area and you will be able to spray it dry again and then pack it with gray form-a- gasket and let it set up for 2 days and the reassemble with the trans out and start it to see if your golden .

Originally Posted by 25stevem

In regards to the above post, what do you mean by something more reliable and a engine swap?

Are you thinking about switch over to something other then a Pontiac just due to a rear main leak?

These days with the choices that Pontiacs have for seals if you can’t get one of these to not leak on you, then it’s not the seals fault, it’s a installation issue!

why is there 2 of you now?

[tom s]

Im 100% with the 1 pc seal and 50/50 with the 2 pc seal.FWIW,Tom

[rohrt]

https://www.youtube.com/watch?v=GQmfLtyMCFw

I wonder if the seal is put in backwards or maybe a core shift issue.

[PDC]

Good God how I don’t miss this. I had two ‘traditional’ Poncho builds in a pair of ‘73 Trans Ams for 8 years and 10 years each. Both very well built engines that made solid power and ran well. Both leaked out the rear main. One went back to the original builder who pulled the engine and replaced the rear main with a Graph-Tite. It rotated in the groove and leaked.

I ended up finding an old school, local mechanic who advertised as a transmission shop, but knew Buick / Pontiac / Olds like nobody’s business. He did 2 engine out rear main seal replacements with 1-piece Viton rear main seals. We also swapped fresh aftermarket oil pans from BOP along with 1-piece Viton pan gaskets. The 455 was literally bone-dry for as long as I owned it. The 400 stroker started weeping about a dime sized spot after a good hard drive. Wipe it up after parking, and no more would drip. We wondered it if wasn’t seeping through the deeper serrations in the aftermarket stroker crank - but he did wipe the serrations down with Emory cloth and mineral spirits before re-assembling.

Rear main seal leaks can be a nightmare. Gotta’ ask yourself how much is actually leaking - if it interferes with the pressure plate / clutch (on manual trans cars) - and how much it really robs you of your ability to just enjoy the car. If its a dime to a quarter sized drop after a day of enjoying the car, probably not worth an engine out rear main replacement.

[blueghoast]

There was a video on you-tube about how to fit the one peace rear seal.
Don't remember the name, would have to do a search for it.
It was pretty interesting though. Good luck..

GT

[Fdby6017]

Going to give it a shot at 2 piece vitron... i have a classic car shop lined up....righy now i lose about 2/3 to 3/4 qt ever 2 tanks fuel.....bottom car is cover in oil🤦*♂️gotta luv the armchair qb who knows how to fix it from his swival seat

[pont3]

The "main" reason I have LS engine in one of my Pontiacs. I like Pontiacs as much as anyone else, and have owned or currently own more than the average person here. My first Pontiac was back in 1975, a 1972 GTO. It didn't leave any stains on the gravel at our family home, but there was oil seeping every where. A little gunk kept it clean. Then, in 1979 I moved up to a '77 GP SJ. Again, no driveway stains but seepage everywhere.

Since then during the '80s and '90s, I've acquired various Pontiacs that I have tried to seal PERSONALLY, and farmed out professionally. I drive mine regularly, and none have succeeded.

I feel the problem is that once these engines get machined away from factory spec, aftermarket sealing materials simply cant compensate, especially since their tolerances aren't spot-on with factory specs. Replacement cranks and such are simply going to have differences. Add in the fact that rubber composition isn't the same and who the hell knows?

Now I'm gonna get hammered for this, but here is my advice. If you only drive your vintage Pontiac to shows and less than three thousand miles a year, disregard. But if you like the styling of your vintage Pontiac, and desire to drive it on a REGULAR basis, consider putting that vintage Pontiac engine in hybernation, and let a more modern engine relieve you of those headaches. Then, if you decide to sell, reinstall the vintage engine.

You can literally take a 150k mile pull out complete LS engine for under 1k and have a more reliable. leak-free engine completely installed for much less than what the cost of a proper Pontiac rebuild, that is still prone to leaks and other problems, would cost. LS engines are easily converted to carbs so if you don't want the expense of fuel injection you can still have the same RELIABAL, leak-free power.

See, these Pontiac diehards here think that everybody has the deep pockets to keep paying the so-called pros big bucks to continue to chase seemingly simple issues. But they never go away and you keep spending and spending and spending. Sorry, folks, I've had enough.

[lust4speed]

Guess I learned something from your post. While my Pontiac engines seal up great and don't leak after a rebuild, my Yukon XL with an LS engine marks it's territory wherever it is parked.

So I can pull out one of these leaky LS engines and they magically will stop leaking when dropped in an old Pontiac?

[will slow gto]

Originally Posted by Fdby6017

My rear main is leaking....66 389 tri power....i fear going thru this repair...knowing it may leak again....had same issue many yrs ago on a different 66. Im considering motor swap to something more reliable.

You might also consider throwing out the baby with the bath water.

[will slow gto]

Originally Posted by pont3

The "main" reason I have LS engine in one of my Pontiacs. I like Pontiacs as much as anyone else, and have owned or currently own more than the average person here. My first Pontiac was back in 1975, a 1972 GTO. It didn't leave any stains on the gravel at our family home, but there was oil seeping every where. A little gunk kept it clean. Then, in 1979 I moved up to a '77 GP SJ. Again, no driveway stains but seepage everywhere.

Since then during the '80s and '90s, I've acquired various Pontiacs that I have tried to seal PERSONALLY, and farmed out professionally. I drive mine regularly, and none have succeeded.

I feel the problem is that once these engines get machined away from factory spec, aftermarket sealing materials simply cant compensate, especially since their tolerances aren't spot-on with factory specs. Replacement cranks and such are simply going to have differences. Add in the fact that rubber composition isn't the same and who the hell knows?

Now I'm gonna get hammered for this, but here is my advice. If you only drive your vintage Pontiac to shows and less than three thousand miles a year, disregard. But if you like the styling of your vintage Pontiac, and desire to drive it on a REGULAR basis, consider putting that vintage Pontiac engine in hybernation, and let a more modern engine relieve you of those headaches. Then, if you decide to sell, reinstall the vintage engine.

You can literally take a 150k mile pull out complete LS engine for under 1k and have a more reliable. leak-free engine completely installed for much less than what the cost of a proper Pontiac rebuild, that is still prone to leaks and other problems, would cost. LS engines are easily converted to carbs so if you don't want the expense of fuel injection you can still have the same RELIABAL, leak-free power.

See, these Pontiac diehards here think that everybody has the deep pockets to keep paying the so-called pros big bucks to continue to chase seemingly simple issues. But they never go away and you keep spending and spending and spending. Sorry, folks, I've had enough.

Or you can just put a piece of cardboard on the garage floor under your real Pontiac engine. Costs a lot less than $1k too.

[pont3]

Originally Posted by lust4speed

Guess I learned something from your post. While my Pontiac engines seal up great and don't leak after a rebuild, my Yukon XL with an LS engine marks it's territory wherever it is parked.

So I can pull out one of these leaky LS engines and they magically will stop leaking when dropped in an old Pontiac?

First off, I would guess that your Yukon has more than 150k miles. You didn't state what year it is but I would bet that it's 2003 or older. And I will also bet that most rebuilt old pontiac engines (that are used regularly) leak more than any old LS.

Please, understand, my problem is NOT with Pontiac designed engines, or what they represented in it's heyday. My problem is with replacement parts that were designed (hit and miss as they are) for STOCK engines. Trying to make these questionable parts conform with AFTERMARKET parts is going to be a challenge.

My whole point is, If you want to show you vintage Pontiac and drive it occasionally, keep it stock. If you want to daily drive your vintage Pontiac and have a reliable drivetrain to motivate it, put your vintage drivetrain into hybernation and use a more modern LS. You can use carbureted or FE. Either way, it will give you far more enjoyment than constantly chasing problems that the industry has left behind. You can continue to chase high dollar parts to keep your car original, but will never again function the way they were designed.

I own my vintage cars to enjoy them, not to wait for sale to the next highest bidder.

I currently own four LS engine equipped vehicles. 1. 2004 GTO that I bought new in 2004. Currently has 100280 miles, not one single drip on my driveway, some aging gasket seepage noted, but no dirty driveway.

2. 2004 GMC Envoy SLT w/5.3 bought w/80k miles , currently with 120111 miles. No drips on my driveway.

3. 1972 Lemans that had the LS1 conversion back in 2008. No leaks but seepage due to aging gaskets. Engine has 89k miles,

4. 2006 GTO w/11200 miles, bought new. Not driven enough to make a comment. But currently no leaks on my garage floor.

My personal experience dates back well into the mid seventies when it comes to Pontiacs. And I have not been without a Pontiac since my first purchase in 1975 of a '72 GTO.

I don't know who builds your engines, but everyone I've tried from SC, to KS, MO. None of these engine builders have found success. And yes, they were all professional shops. Don't get me wrong. It's not the engines. It's the subpar aftermarket products. And after forty some years, I'm done.

[Sirrotica]

If done the way the Pontiac shop manual shows, the graphite rope seals don't leak. I've done many Pontiac, olds, olds diesel, and buick rear main seals with very good success. Working in a dealership, you get to do it over the second time for free, if it leaks the first time. If you do a couple over for free, you make sure they don't leak the first time.

I've packed the agitator shaft on a storage tank with graphite rope seals that has thousands of gallons of fluid pushing on them with no leaks.

At this juncture of time any Pontiac engine that still has a factory seal in it in most likely rotted, and leaking, the rest have been replaced. Many times they were done with the rope that didn't have any asbestos in it. (OEM rope seals were made with asbestos, that was later prohibited). That non asbestos rope material just doesn't hold up, and leaks frequently.

The correct size graphite rope seals as well as the old asbestos rope seals did seal the cranks on Pontiacs, as well as the olds, and buicks..

I'm not buying the one piece LS, and SBC seals don't leak, I've replaced plenty of the one piece seals in GM engines. V8s six, and four cylinders with the one piece seals that leak frequently. Same goes for the 2 piece neoprene seals that chevy, AMC, and some fords used, I've replaced all of them.

I've never tried the rubber aftermarket seals in a Pontiac, but if you look at the serrated area of the crank on any GM OEM cranks that were intended to be used with a rope seal. I would never expect that raised toothed area not to ruin the sealing lips on any one, or two piece seal, it's like running a file over the sealing lip.

Putting an LS engine in a Pontiac because you couldn't stop a rear main oil leak is pretty laughable. FWIW, my 144,000 mile 05 GTO leaks oil, bought it new so I know no one has had their hands on the engine. My 71 455 that I rebuilt in 89, doesn't leak so I guess I should put a 455 in my 05 GTO.....

[Dragncar]

Originally Posted by pont3

The "main" reason I have LS engine in one of my Pontiacs. I like Pontiacs as much as anyone else, and have owned or currently own more than the average person here. My first Pontiac was back in 1975, a 1972 GTO. It didn't leave any stains on the gravel at our family home, but there was oil seeping every where. A little gunk kept it clean. Then, in 1979 I moved up to a '77 GP SJ. Again, no driveway stains but seepage everywhere.

Since then during the '80s and '90s, I've acquired various Pontiacs that I have tried to seal PERSONALLY, and farmed out professionally. I drive mine regularly, and none have succeeded.

I feel the problem is that once these engines get machined away from factory spec, aftermarket sealing materials simply cant compensate, especially since their tolerances aren't spot-on with factory specs. Replacement cranks and such are simply going to have differences. Add in the fact that rubber composition isn't the same and who the hell knows?

Now I'm gonna get hammered for this, but here is my advice. If you only drive your vintage Pontiac to shows and less than three thousand miles a year, disregard. But if you like the styling of your vintage Pontiac, and desire to drive it on a REGULAR basis, consider putting that vintage Pontiac engine in hybernation, and let a more modern engine relieve you of those headaches. Then, if you decide to sell, reinstall the vintage engine.

You can literally take a 150k mile pull out complete LS engine for under 1k and have a more reliable. leak-free engine completely installed for much less than what the cost of a proper Pontiac rebuild, that is still prone to leaks and other problems, would cost. LS engines are easily converted to carbs so if you don't want the expense of fuel injection you can still have the same RELIABAL, leak-free power.

See, these Pontiac diehards here think that everybody has the deep pockets to keep paying the so-called pros big bucks to continue to chase seemingly simple issues. But they never go away and you keep spending and spending and spending. Sorry, folks, I've had enough.

Once you put a LS in a old PONTIAC it is no longer a PONTIAC.
Its about the engine more than anything else. A 69 Chevy, Olds, Buick and Pontiac were the same car, the difference was the engines.
Its all about the engine, the sound, the torque.
And not being like everyone else.
Pontiacs with LS engines in them are lame,lame and lame.
When I see those I turn and walk away. Weak.

[dataway]

Basically, if driven ... old cars leak, old engine designs leak. I don't want them leaving puddles, but "drops" are just the nature of the beast I think. I try to think back to when I was driving them as daily transportation .... how much of a leak would I have tolerated back then. Probably a lot more than I'd tolerate now.

I grew up having to park my cars on the street cause my Dad didn't want them leaking in the driveway next to his new cars.

[djustice]

I have the 2 piece viton (3.25") rigth now, considering getting the 1 piece version, as i am going to pull the motor soon.
Here in Norway we fail the bi-anual vihecle inspection if 1 drop of fluid hits the floor during the 1 hour inspection. We then get 2 months to fix the leak and come in for a post inspection.
If it still drips the vihecle fails and licence plates are taken, until we can fix the problem again.
Needless to say i am abit anxious about this as i am due in 2023 (the last inspection as the vihecle is then 50 years)