[gtorich]

Seeing what you guys thought of this..........just had the motor re-ringed after 2 rebuilds over the years since 2007........always used oil or leaked, but never on the floor as this one does............never believed in the stop leak stuff but it does seem to work some here.............1st pic is about a weeks worth of driving, the big blog was from a few small spots that dripped alot when i had the cardboard standing up..............but the other pics are usually what i have after driving the car and shutting it off................usually get a small drip here or there up till about 48 hrs.

Probably no way to tell, just wondering if the anti-rotational holes were not plugged................the builder said they were, and he did a smoke test and found no leaks....................starting to wonder if he meant he smoked a joint then did the test.

Thinking im not gonna try to fix this motor again, 3 strikes and your out..........not having hacks work on this car, so im thinking something is not right with the motor itself.

Never had a leak like this..................is this about the norm for a pontiac to be leaking after driving..................noticed if im really beating on the car, the leak is worse.

Rich

[Sirrotica]

Pontiacs are like HD motorcyles, they're not leaking, they're marking their territory..........

Having worked on these cars when they were new, to only a few years old ( Co-op in 1970, at the local Pontiac dealer). Plus having worked at GM dealerships such as olds, and buick, which also used rope seals, it was few, and far between to see a completely dry rear main seal on one of these engines, they mostly all seeped after 10,000 miles. People that owned them were told it was inevitable, and was normal. After a few years some of them leaked pretty bad.

My parents had a 63 Bonneville that had low miles on it, that they bought used in 1965. It leaked from the day they bought it, to when it went to the boneyard. It got slowly worse as the years rolled by too.

My father was a mechanic most of his adult life, and knew he would have to pull the engine to put a new rear main seal on it. He was going to do it at one point, then I guess he talked himself out of it. It was kind of unusual, for my dad to put up with something like this, because we had just gotten the driveway paved with asphalt while he owned that car, and new asphalt doesn't bode well with a leaking rear main seal.........

Instead of putting a new rear main in it he bought a 69 GP that didn't do anymore than slightly seep. I bought the 63 from him and used it for a winter car, until some guy hit it during a snowstorm, and I sent it to the boneyard.

So most of them leaked to varying degrees, people just poured more oil in them. Seldom did they get repaired, because the engine had to come out to do the job right, and most places would tell their customers that it may leak worse than it did before they "fixed it". Code for ,"We really don't want the job at all".

While I worked on buicks at a dealership it wasn't really out of the norm for the factory to put a couple of rear main seals in buick engines, and if they couldn't get the rear main sealed to a customers expectation, they would shortblock the car under warranty. I did a couple buicks, and put new shortblocks in them while I worked there. You can look the rear main area over, and see nothing amiss, but they just won't seal sometimes. It would be hard to determine if the rear main grove, and the crank weren't on the exact same axis, making the seal light on one side of the crankshaft, leading to a slight leak. Pontiac blocks when machined for the main seal groove, were all over the place, not a bunch of time was spent in that area of the block.

Just relaying real world experieces here of having worked on these cars when there were hundreds of thousands of them on the roads, from a mechanics standpoint.

[NeighborsComplaint]

It's Pontiac's Achilles heel. Well, that and the poor flowing heads. Oh, and the antiquated cooling system design, the grand canyon lifter valley, the short valve spring installed heights, the heat soaking starter solenoid, and the alternator up on top looking like a Ford flathead. I think that pretty much covers it.

When you get the leaks down to the point a pizza box will catch them, you've got it.

[mgarblik]

These old engines with 2 piece rear seals leak some. Very few are leak free as mentioned by Sirotica. Pontiacs worse than many because of the lousy wide pan seal area as well. I did 13 oil pan R+R's at the medium size Pontiac dealer I worked at in one week! These were all under warranty in 1979. Mostly Pontiacs, a couple were 403 Olds in TA's. Very common issue. We would make one attempt to seal them up under warranty. If still leaking, the zone had to get involved. I did the best I could, using the special brass tool to mash extra pieces of rope into the upper groove. All repairs had to be made with engine in the chassis. I had about a 75% success rate of being leak free. The rest still dripped a little.
My current street engine has a BOP 2-piece seal, which I have had the best luck with. On the dyno, bone dry. In the car, it had a small drip for about 500-700 miles. Then it quit leaking. Very hard to predict.

[64speed]

Mine started leaking as soon as I started driving regularly. The one I blew up didn’t drip a drop. Unless it just gets crazy I’ll just add oil if I need too.

[Gach]

It sucks, I would just keep and eye on it. Hey you never know listen to the reply's it may go away. Who knows

[b-man]

Keep a pan or a piece of cardboard under it.

Wipe it down underneath at oil change time.

Just drive it, life’s too short to worry big about a small issue.

[Verdoro 68]

Ah man. I have such PTSD from my rear main issues.

Mine used to leak about that much before I rebuilt it. It was annoying, but I just wiped it down everyone once in a while.

[PAUL K]

Originally Posted by b-man

Keep a pan or a piece of cardboard under it.

Wipe it down underneath at oil change time.

Just drive it, life’s too short to worry big about a small issue.

That's my second favorite joke.... I designed a Harley Davidson oil pan gasket.... It's a tray you slide underneath the engine when you park it.

[PAUL K]

I'd check things out. If its leaking from the RMS and doesn't get worse I'd live with it. Sometimes you can get an old engine sealed up perfectly. A lot also leak. If you watch an old Adam 12, Emergency or Starsky and Hutch pay attention to the helicopter shots of the roads. They're literally oil slicks down the middle of the lanes in all of the scenes. All the engines back then leaked oil. Technology has gotten better for modern engines to be leak free.The Pontiac RMS have got worse. The material oil pan gaskets are made from has got worse. If GM couldn't keep them from leaking when they were new, I wouldn't expect 50 years and many miles of wear to improve the situation. If you do change the seal you have three seals you've tried and failed. Choose the fourth one wisely.

[Dragncar]

Originally Posted by Sirrotica

Pontiacs are like HD motorcyles, they're not leaking, they're marking their territory..........

Having worked on these cars when they were new, to only a few years old ( Co-op in 1970, at the local Pontiac dealer). Plus having worked at GM dealerships such as olds, and buick, which also used rope seals, it was few, and far between to see a completely dry rear main seal on one of these engines, they mostly all seeped after 10,000 miles. People that owned them were told it was inevitable, and was normal. After a few years some of them leaked pretty bad.

My parents had a 63 Bonneville that had low miles on it, that they bought used in 1965. It leaked from the day they bought it, to when it went to the boneyard. It got slowly worse as the years rolled by too.

My father was a mechanic most of his adult life, and knew he would have to pull the engine to put a new rear main seal on it. He was going to do it at one point, then I guess he talked himself out of it. It was kind of unusual, for my dad to put up with something like this, because we had just gotten the driveway paved with asphalt while he owned that car, and new asphalt doesn't bode well with a leaking rear main seal.........

Instead of putting a new rear main in it he bought a 69 GP that didn't do anymore than slightly seep. I bought the 63 from him and used it for a winter car, until some guy hit it during a snowstorm, and I sent it to the boneyard.

So most of them leaked to varying degrees, people just poured more oil in them. Seldom did they get repaired, because the engine had to come out to do the job right, and most places would tell their customers that it may leak worse than it did before they "fixed it". Code for ,"We really don't want the job at all".

While I worked on buicks at a dealership it wasn't really out of the norm for the factory to put a couple of rear main seals in buick engines, and if they couldn't get the rear main sealed to a customers expectation, they would shortblock the car under warranty. I did a couple buicks, and put new shortblocks in them while I worked there. You can look the rear main area over, and see nothing amiss, but they just won't seal sometimes. It would be hard to determine if the rear main grove, and the crank weren't on the exact same axis, making the seal light on one side of the crankshaft, leading to a slight leak. Pontiac blocks when machined for the main seal groove, were all over the place, not a bunch of time was spent in that area of the block.

Just relaying real world experieces here of having worked on these cars when there were hundreds of thousands of them on the roads, from a mechanics standpoint.

That rear main groove is one of the reason I like the BOP one piece. Sand it to fit the grove.
Mine does not leak a drop.
Rich could try a V pump. Negative pressure might help and its bolt on.

[gtorich]

Hey thanks guys, i"ll just keep an eye on it for now...................dont remember the 1st seal, but the 2nd was the best gasket rear main, the one in there now is a bop 1 pc..........just wondering if they didnt fill the anit-rotation holes like your supposed to on a 455............like i said, im not gonna try again with this motor, gonna try a different one.

Rich

[78w72]

Hi Rich. I mentioned my opinion & experience on this when we emailed awhile back... I dont have stories of stock engines with rope seals 40-50 years ago but do have experience with the BOP seals & normal pan gaskets as well as an original rope seal in an 81 turbo & other engines with rope seals back in the 90's. My 81 with just under 30k miles is what I consider leak free for a pontiac even using synthetic oils, it will seep a little after a full season that just gets a film on the rear pan area, I wipe it down once or twice a season & dont worry about it.

On my 467 stroker I had what I thought was a RMS leak, after pulling it 2 times and taking it back to the shop to replace the BOP 2 piece RMS, it ended up being the rubber U seal of the pan gasket, its the older style 3 tab U seal on a milodon 7qt pan, whats funny is it leaked worse after the 1st RMS/pan replacement than it did when I installed the pan myself...

Long story short, on the final try I ended up using the thick cork U seal gasket explained by Mr Pbody & others on here, we kept the RMS in place since the shop said it was fine & used the cork U gasket with ultra black sealant using a standard felpro pan gasket, not the 1 piece BOP.. its been "leak free" for 7-8 years now with only some seepage that doesnt leak anything on the ground regardless of how its driven, I wipe it down once a season & its basically dry.. for a pontiac. Same for another 78 400 I have thats uses the BOP 2 piece RMS but has the later style 5 tab U seal, standard felpro pan gasket there too. If you try to fix the pan leak again I would suggest the cork U seal & a regular felpro gasket, Ive heard too many leak issues with the 1 piece gasket... but then again lots of people like them so its kind of a crap shoot as to how they are installed I guess. https://www.pontiacstreetperformance...sp/Sealit.html

As a side note, I used to have a jeep cherokee with the 4.0 as a daily driver for almost 20 years & 200k+ miles, they are notorious for RMS leaks, best thing I found was to use non synthetic oils & a little lucas oil stabilizer, tried a few RMS leak stop additives & the best one was blue devil, but it only lasted for 1-2 oil changes & the leak came back, I used the poor mans harley gasket mentioned above for the last 3 or 4 years... cardboard under the pan!

Hope you can get the leak fixed or improved to live with it, use non synthetic oil if youre not & try some lucas or other RMS stop leak just to see what it does. & snug up the pan bolts a little if they havent been checked/snugged since installed.... or consider a vac pump as mentioned.

[jhein]

Could a malfunctioning PCV system cause a leak that bad?

[gtorich]

Thanks again Scott............i saved that link you sent me awhile back...........im using regular oil, will look into that lucas stabilizer , i have the blue devil in the car now, seems to help some.................putting the car away for the winter next week, if it stays like this, im gonna live with it..................

On a side note, i admire you guys that seem to pull these motors out like changing pants.........lol..................ive done it 3 times, and i just cant see doing it for the 4th time...........im 72 now, this pulling motors is losing its appeal...................

But i do appreciate all the help i get from you guys.....................have a great day

Rich

[Verdoro 68]

Originally Posted by jhein

Could a malfunctioning PCV system cause a leak that bad?

Some folks say the Wagner dual flow PCV helped with their leaky engine because it ensures the crankcase is under vacuum at all times. Other folks say it's snake oil. At $130 it's a little of an expensive gamble. That said, I run one because I picked it up when I was grasping at straws trying to solve my leak problem.

[jhein]

Originally Posted by Verdoro 68

Some folks say the Wagner dual flow PCV helped with their leaky engine because it ensures the crankcase is under vacuum at all times. Other folks say it's snake oil. At $130 it's a little of an expensive gamble. That said, I run one because I picked it up when I was grasping at straws trying to solve my leak problem.

I saw that piece when someone posted about it, maybe it was you. Did you need the adapter to run it in the valley pan?

[Verdoro 68]

Originally Posted by jhein

I saw that piece when someone posted about it, maybe it was you. Did you need the adapter to run it in the valley pan?

Yes. They have a kit specifically for a Pontiac. It kicks the price up another $30.

The more cost effective thing to try might be to find an NOS PCV valve which apparently flow better than the modern replacements.

Old thread on it: https://forums.maxperformanceinc.com...d.php?t=784178

[i82much]

I bought the Wagner PCV and the adapter, plus this:

https://www.amazon.com/gp/product/B0...e?ie=UTF8&th=1

Using an off-the-shelf PVC valve vs. the Wagner after adjustment, I was able to see on the manometer that there was noticeably more crankcase vacuum with the Wagner valve. About twice as much. That's a basic 505-CID, 10:1, 87 cc edelbrock round ports with an RPM intake, old faithful 1.0 cam, and 1 7/8 doug's headers.