BP oil and leak

[tobluforu]

I have always had some oil dripping from the back of the motor which I'm pretty sure is the flywheel seaI and I always used valvoline 20-50 racing. I put some 20-50 bp oil in and I'm not sure if its coincidence or just that the seal decided to let loose, but I have a hell of a lot of oil coming out now. Almost to a point that I'm not going to drive it. Could the bp oil be causing this horrendous oil leak on my 72, did it just take a leak and compound it on my 72? I mean this is crazy!

[mickey356]

All that salt water in it probably ate away the seal.

[nesslar]

BP is partially synthetic; probably MOSTLY so; go back to the real stuff. Many guys have had better luck with dino oil; and ynot, it's REAL... Speaking only from experience......

[tobluforu]

Originally Posted by mickey356

All that salt water in it probably ate away the seal.

Car has not been driven in the rain for the past 10 years or so and never in the snow , but it was a Ca car up until 3 years ago.

[Flieger]

I think he is making a smart remark with regards to the BP oil spill, not the Brad Penn.

Oddly, I seemed to have fewer leaks going from Castrol GTX to Brad Penn. The Brad Penn stays thicker longer, too.

[BGCarrera32]

Your car is 38 years old. Don't blame the oil.

[Por_sha911]

Brad Penn is 10% synthetic - certainly not enough to create a major leak. Its probably just your seal just gave up the ghost.

[RichardM912]

1. What are the respective API gasoline engine oil specifications of the two products - that is, what letter comes after the "S" in the performance levels claimed? Also, is there a "C" performance claimed and, if so, what letter comes after the "C"? The API "S" and "C" specifications determine how much detergency/dispersancy the oil will have. A change in this level can clean out a borderline seal and trigger a leak.

2. Are the oils full or partial synthetics or are they mineral oil based? If mineral oil they will have to use a Viscosity Index Improver (VII) to achieve a 20W/50 viscosity grade. If synthetic, they probably won't need to. VIIs are not necessarily shear stable and so, in use, oils that contain them can thin out. However, the amount of VII needed for a 20W/50 is not huge and so the thinning effect should not be massive. Seal failure seems more probable.

[tobluforu]

Yeah I know, it's wishful thinking on my part.

[Hodgey]

Originally Posted by por_sha911

brad penn is 10% synthetic - certainly not enough to create a major leak. Its probably just your seal just gave up the ghost.

+1

[tobluforu]

Update: Took Air cleaner off and a little bit of oil came out of the hose that connects to the oil filter housing-never did this before. There's oil on top of the motor, only in the back, and to the right of the mfi pump. It's super hard to tell but it might be coming from the breather cover, the thermostat, the prssure sender or somewhere else. The plot thickens or thins if we look at it from an oil perspective.

[EarlyPorsche]

I can tell you with 100% certainty that if you used the same weight oil you used to have in the engine that its not the oil. When a seal lets go thats exactly what you will see. Time to pull the engine and when you put it back in use whatever oil makes you comfortable.

[Green 912]

did you overfill? Are you blowing oil out the breather?

[Por_sha911]

Originally Posted by tobluforu

Update: Took Air cleaner off and a little bit of oil came out of the hose that connects to the oil filter housing-never did this before. There's oil on top of the motor, only in the back, and to the right of the mfi pump. It's super hard to tell but it might be coming from the breather cover, the thermostat, the prssure sender or somewhere else. The plot thickens or thins if we look at it from an oil perspective.

Sounds like you overfilled it. How many quarts did you put in? Are you familiar with how to check the level?

[Por_sha911]

Originally Posted by RichardM912

1. What are the respective API gasoline engine oil specifications of the two products - that is, what letter comes after the "S" in the performance levels claimed? Also, is there a "C" performance claimed and, if so, what letter comes after the "C"? The API "S" and "C" specifications determine how much detergency/dispersancy the oil will have. A change in this level can clean out a borderline seal and trigger a leak.

2. Are the oils full or partial synthetics or are they mineral oil based? If mineral oil they will have to use a Viscosity Index Improver (VII) to achieve a 20W/50 viscosity grade. If synthetic, they probably won't need to. VIIs are not necessarily shear stable and so, in use, oils that contain them can thin out. However, the amount of VII needed for a 20W/50 is not huge and so the thinning effect should not be massive. Seal failure seems more probable.

Go here: Branded Lubricants - Engine Oils | American Refining Group, Inc. and click the link under Synthetic Blend Motor Oils marked "Product Bulletin"

[tobluforu]

Originally Posted by Por_sha911

Sounds like you overfilled it. How many quarts did you put in? Are you familiar with how to check the level?

Your kidding right, as I have had car for 19 years, rebulit the motor and have basically done everything to it except align it?

[tobluforu]

Originally Posted by EarlyPorsche

I can tell you with 100% certainty that if you used the same weight oil you used to have in the engine that its not the oil. When a seal lets go thats exactly what you will see. Time to pull the engine and when you put it back in use whatever oil makes you comfortable.

And you are 90 percent wrong. I dumped the holy grail of oil, went back to valvoline 20/50 racing like I have been using for the past 20 years, and the leak is down to what it was before. And that's about 15 drops or less after I drive it. Granted, it needs a new RMS, but I can at least drive it without putting an oil pan under it when I shut it down. When I have the tranny rebuilt next year, the RMS will be replaced and I will re-visit BP once again.

[Por_sha911]

Did you ever discover what caused oil to show up in the hose? Apparently you are more knowledgeable than I so I'll refrain from further long distance guesses.

[Flieger]

Synthetic oils, due to their chemical composition, used to shrink the types of (rubber?) seals used in Porsche and many other old engines. When the manufacturers found this out, they mixed in some seal-swelling additives to balance out the effect and maintain seals. If the previous mineral oil had some seal swelling additives and then one switched to partial synthetic Brad Penn, it could cause an increase in leakage.

Like I said, though, I had fewer/less leakage with Brad Penn from Castrol GTX, both 20W50.

[tobluforu]

Originally Posted by Por_sha911

Did you ever discover what caused oil to show up in the hose? Apparently you are more knowledgeable than I so I'll refrain from further long distance guesses.

Draining and filling up oil in these cars isn't a black art like adjusting the MFI can be. I can only speculate that the little oil that I found in the air cleaner was due to blow-by caused maybe the thinner oil? It sure as hell wasn't from me adding 10 quarts when I should have added 8.
From what I have found I'm not the only one that has had this issue with this oil. The engine was rebuilt 15 years ago; I have auto-xed it over 100 times; ran it at numerous tracks and pretty much have beaten the hell out of it so the seals are old and tired.