Rear Main Seal Leak

[Clone TIE Pilot]

Two piece rear main seals always seep a little oil, its why SBCs went to one piece rear seals beginning in 1986. Any engine with many miles will seep some oil, even LS which are getting long in the tooth by the true definition of "modern." The oil seeps at least help fight rust.

As for engine swapping, the US law is the engine must be the same year or newer than the car and must retain its full emission package. The big issue for this is that the EVAP system can only be tested by locking a car in a airtight chamber for two weeks to truly measure HC leakage from the car. So instead they verify you have a approved, certified, and intact factory EVAP package for the engine type you installed.

 

[Texas82GP]

i live by San Francisco, weather is good.
Yes, i recently learned about zinc not being in today’s motor oil for old cars.

I’ll see how this 20w50 plays out and go from there

thanks for the tips

You're welcome. Straight 30W may be a bit thick in the Bay Area, though my Dad ran it in everything here, under all conditions when I was a kid.

 

[Scoot-71]

I don't recall a sbc ever having a rope style seal, Pontiacs yes, But never a sbc, I will say I am not familiar with a 265 but I would be surprised if it had rope as a seal, even so, many engines will have a 2 piece seal available as a replacement opposed to rope seal.

 

[pagrunt]

I don't recall a sbc ever having a rope style seal, Pontiacs yes, But never a sbc, I will say I am not familiar with a 265 but I would be surprised if it had rope as a seal, even so, many engines will have a 2 piece seal available as a replacement opposed to rope seal.

They did start with rope seals in the '50's, not sure when they changed them.

 

[oldsmobile joe]

Fix the rear main. Cheapest and easiest repair. Call around, check with people in the car clubs, etc. And find someone who can do it.
Your engine is a pontiac design and build. Last year for v8 pontiac motors. With you being in cali, engine swaps would have to approved by your emission station. Your 265 pontiac motor was the only gas v8 offered in that car for that year. The others were a v6 or a diesel.
Don't get caught up in engine swaps or rebuilds. Change oil to a high mileage oil, this oil has the stop leak already in it, or conventional oil with a bottle of stop leak. Something intended to soften and swell the dried out seals.
Then fix the rope seal.
Lastly, keep driving your car and enjoying it.

 

[Texas82GP]

I don't recall a sbc ever having a rope style seal, Pontiacs yes, But never a sbc, I will say I am not familiar with a 265 but I would be surprised if it had rope as a seal, even so, many engines will have a 2 piece seal available as a replacement opposed to rope seal.

It's the Pontiac 265 which has a rope seal.

 

[Ribbedroof]

...or just replace the seal and keep on truckin'.

^^^ THIS ^^^

Honestly, some of you guys must have reading problems. Says he's fine with the car, just doesn't like the leak. Your first instinct seems to be an engine swap, and one that is going to require all the accessory brackets and trans for a different engine platform. Not everyone is looking for max performance.

 

[DRIVEN]

The 265 Chevy and '57 283 had rope seals, I believe. But we're talking Pontiacs.

rubio9800, rope seals are 100 year old technology. It's important that you have realistic expectations here. Rope seals are a little finicky and most of them ooze a little bit, no matter what. They also tend to take some run time to "wear in." So, when you find someone to replace it, just understand that a completely dry engine is very unlikely. If it doesn't leave puddles in the garage or fog up the back of the car, you're doing pretty good. I'd also recommend medium-heavy weight dino oil.

Best of luck to you.

 

[Northernregal]

Proper fix for a pontiac rear main seal,

BOP Engineering, your source for High Performance Buick, Oldsmobile and Pontiac Parts

www.bopengineering.com

 

[ssn696]

This place seems to think a ford 460 seal will fit in a Pontiac 301. Is a 265 similar enough to a 301?

Rear Main Rope Seal - Alternatives For Many Older Engines

Firstly, using a rear main rope seal, is almost a thing of the past. And, has greatly diminished in use. So, the rear main rope seal worked well, in its

dannysengineportal.com