Modern oils and old seals
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GC.
Originally Posted By: Ben99GT
Originally Posted By: JLR
What is GC?
German made Castrol Syntec 0W-30
NO NO! GC has PAO and is a great synthetic oil but PAO base oils are not the greatest for seals. I would use anything Pennzoil or Valvoline in that order.
Originally Posted By: JLR
What is GC?
German made Castrol Syntec 0W-30
NO NO! GC has PAO and is a great synthetic oil but PAO base oils are not the greatest for seals. I would use anything Pennzoil or Valvoline in that order.
didn't you say before that this engine was rebuilt in the late '90s and the car gets little use? So for seal discussion sake, it's a modernish engine, not a 45yr old engine. Heck, the seals on my car are older and have much much more mileage than this car. (Of course, my car leaks a bit of everything so it's a bad comparison) Are the seals currently leaking? The synthetic HDEOs (Rotella T6, Delvac 1, etc) previously recommended should preform excellently and protect the older design engine at the same time. If the seals are not currently leaking, high mileage oils could, in theory, cause them to swell which could, again in theory, lead to premature failure or so the argument goes. Whether that actually happens or not is debatable. Assuming the seals are currently okay, I would avoid oils with seal swelling additives and just stick with high quality oils that will keep your seals as healthy as possible. All modern oils will fit this requirement.
Originally Posted By: JLR
I have been researching my options and have decided to go with rotella t 6. Your help is greatly appreciated.
That's a good choice, T6 is a good oil.
I have been researching my options and have decided to go with rotella t 6. Your help is greatly appreciated.
That's a good choice, T6 is a good oil.
Originally Posted By: blue94
didn't you say before that this engine was rebuilt in the late '90s and the car gets little use? So for seal discussion sake, it's a modernish engine, not a 45yr old engine. Heck, the seals on my car are older and have much much more mileage than this car. (Of course, my car leaks a bit of everything so it's a bad comparison) Are the seals currently leaking? The synthetic HDEOs (Rotella T6, Delvac 1, etc) previously recommended should preform excellently and protect the older design engine at the same time. If the seals are not currently leaking, high mileage oils could, in theory, cause them to swell which could, again in theory, lead to premature failure or so the argument goes. Whether that actually happens or not is debatable. Assuming the seals are currently okay, I would avoid oils with seal swelling additives and just stick with high quality oils that will keep your seals as healthy as possible. All modern oils will fit this requirement.
Great post. It is often what is UNSAID that is most important in internet queries!
didn't you say before that this engine was rebuilt in the late '90s and the car gets little use? So for seal discussion sake, it's a modernish engine, not a 45yr old engine. Heck, the seals on my car are older and have much much more mileage than this car. (Of course, my car leaks a bit of everything so it's a bad comparison) Are the seals currently leaking? The synthetic HDEOs (Rotella T6, Delvac 1, etc) previously recommended should preform excellently and protect the older design engine at the same time. If the seals are not currently leaking, high mileage oils could, in theory, cause them to swell which could, again in theory, lead to premature failure or so the argument goes. Whether that actually happens or not is debatable. Assuming the seals are currently okay, I would avoid oils with seal swelling additives and just stick with high quality oils that will keep your seals as healthy as possible. All modern oils will fit this requirement.
Great post. It is often what is UNSAID that is most important in internet queries!
Use an HM oil, like Mobil 1 HM.
Originally Posted By: chubbs1
Originally Posted By: Ben99GT
Originally Posted By: JLR
What is GC?
German made Castrol Syntec 0W-30
NO NO! GC has PAO and is a great synthetic oil but PAO base oils are not the greatest for seals. I would use anything Pennzoil or Valvoline in that order.
Then why the big problem in the past when Mercedes-Benz did not specify GC for cars sold in the US and the owners who used GC had no problems with main seals front and back, but the owners who did not use GC had leaks so bad that Mercedes had to replace those seals regardless of miles, and then specified GC.
Originally Posted By: Ben99GT
Originally Posted By: JLR
What is GC?
German made Castrol Syntec 0W-30
NO NO! GC has PAO and is a great synthetic oil but PAO base oils are not the greatest for seals. I would use anything Pennzoil or Valvoline in that order.
Then why the big problem in the past when Mercedes-Benz did not specify GC for cars sold in the US and the owners who used GC had no problems with main seals front and back, but the owners who did not use GC had leaks so bad that Mercedes had to replace those seals regardless of miles, and then specified GC.
PAO isn't hard on seals so much as it doesn't cause seal to swell like more conventional oils. This is made up for with seal swell additive.
Using a oil with seal swelling additives, can cause good seals to leak? How is that possible in theory?
Originally Posted By: finalyzd
Using a oil with seal swelling additives, can cause good seals to leak? How is that possible in theory?
The additive softens and weakens the seals, then the swelling increases the compressive force and drag on them.
OTOH, if you seals are old, shrunken and dried out, the swelling can make them fit better and conform better to their mating surface.
Using a oil with seal swelling additives, can cause good seals to leak? How is that possible in theory?
The additive softens and weakens the seals, then the swelling increases the compressive force and drag on them.
OTOH, if you seals are old, shrunken and dried out, the swelling can make them fit better and conform better to their mating surface.
Originally Posted By: XS650
Originally Posted By: finalyzd
Using a oil with seal swelling additives, can cause good seals to leak? How is that possible in theory?
The additive softens and weakens the seals, then the swelling increases the compressive force and drag on them.
OTOH, if you seals are old, shrunken and dried out, the swelling can make them fit better and conform better to their mating surface.
You would think a high mileage oil would keep them soft and pliable, so they don't leak.
Originally Posted By: finalyzd
Using a oil with seal swelling additives, can cause good seals to leak? How is that possible in theory?
The additive softens and weakens the seals, then the swelling increases the compressive force and drag on them.
OTOH, if you seals are old, shrunken and dried out, the swelling can make them fit better and conform better to their mating surface.
You would think a high mileage oil would keep them soft and pliable, so they don't leak.
Originally Posted By: JimPghPA
Originally Posted By: chubbs1
Originally Posted By: Ben99GT
Originally Posted By: JLR
What is GC?
German made Castrol Syntec 0W-30
NO NO! GC has PAO and is a great synthetic oil but PAO base oils are not the greatest for seals. I would use anything Pennzoil or Valvoline in that order.
Then why the big problem in the past when Mercedes-Benz did not specify GC for cars sold in the US and the owners who used GC had no problems with main seals front and back, but the owners who did not use GC had leaks so bad that Mercedes had to replace those seals regardless of miles, and then specified GC.
And you have the case study saying every benz that used GC has never had a seal leak. And that all other cars useing other oils had main seal leaks???????
Originally Posted By: chubbs1
Originally Posted By: Ben99GT
Originally Posted By: JLR
What is GC?
German made Castrol Syntec 0W-30
NO NO! GC has PAO and is a great synthetic oil but PAO base oils are not the greatest for seals. I would use anything Pennzoil or Valvoline in that order.
Then why the big problem in the past when Mercedes-Benz did not specify GC for cars sold in the US and the owners who used GC had no problems with main seals front and back, but the owners who did not use GC had leaks so bad that Mercedes had to replace those seals regardless of miles, and then specified GC.
And you have the case study saying every benz that used GC has never had a seal leak. And that all other cars useing other oils had main seal leaks???????
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