Seal Life: DINO vs. Synthetics

[kgb007stb]

Hey guys, one issue that I have been thinking for a long time is how do synthetics and dinos affect seal longetivity.

Let’s assume that we start with a completely clean engine, and for the life of that engine whether we choose to use dinos or synthetics this engine would be maintained by someone who knows a good deal about car maintenance and could keep the internal parts clean for the life of the engine. If we assume that the seals were kept clean, and had ample oil supply for their entire life, would dino’s prolong the seal life as compared to synthetics?

Why do I ask? I had a car that was switched to synthetics at around the 30k mark, had good maintenance its entire life and at around the 140K mark developed a seal leak. I sold it right before I found this site, but for those that do develop seal leaks and use AUTO-RX to clean their engines, Frank is consistently saying that one should use dinos after the rinse phase for couple more OCIs before switching to synthetics to give seals time to return back to their pliable state.

Do dinos contain some additive that synthetics do not have which would cause it to lengthen seal life? I know people who are past the 200K mark on dinos without any seal failures what so ever. Reading through some of the more rigorous discussion about the dino VS synthetics, I do feel that the SM rated oils are closing the gap, especially when so many pass the 200K mark with clean worry free engines.

 

[blackdiamond]

I think the synthetic side of the story might be related to some of the early seal problems that kept people from switching back to conventional from synthetic. This is why some people still believe that once you go synthetic you can't go back.

I think any of the Group III base oils should be essentially identical to conventional oils as far as seals. The Group IV (POA) are the ones that I THINK I have read/heard that have some seal issues without the proper additives and the Group V (PE) can actually be used as a seal conditioner.

From what I have read from Frank (Auto-RX) is that High Mileage oil and synthetics tend to expand, and somewhat weaken, seals and conventionals while the Auto-RX just cleans the gunk out from around the seals that create leak paths, they don't really modify the seal material itself.

Again, this is just my understanding from what I have read and it may be very flawed.

 

[Steve S]

Both syn oils and petro oils are formulated to be nice to seals.

 

[Quest]

IMHO both conventional and synthetic should bear proper seal-swelling properties when blended properly.

All other factors that may have contributed to the acceleration of seal deterioriation all comes from outside (e.g. external factors, such as oil contamination, oxidation, abrasion, acids, acid-related corrosion to seal elastomers, etc.)

My 2c's worth.

 

[TallPaul]

And high mileage oil is even better for seals.

 

[blackdiamond]

Quote:

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And high mileage oil is even better for seals.

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Frank from Auto-RX seems to think otherwise, or at least that is my understanding.

http://theoildrop.server101.com/forums/s...ge=0#Post874104

 

[TallPaul]

Quote:

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Quote:

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And high mileage oil is even better for seals.

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Frank from Auto-RX seems to think otherwise, or at least that is my understanding.

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I disagree. Here is what Valvoline.com says about Maxlife re seals:

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MaxLife motor oil extends the life of higher mileage engines by fighting the four major causes of breakdown – leaks, deposits, sludge and friction. The synthetic blend formula contains our Multi-Life™ additive system designed to combat these problems unique to older engines. ...

Special seal conditioners rejuvenate seals within the engine block to help prevent oil leaks that lead to sludge and deposits.

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[oilyriser]

http://www.epa.gov/Region3/rcei/images/seal.gif

I womder if synthetic would have been better.

I've noticed the seal rubber gets hard and cracked, but have not found the answer to how to prevent it.

 

[Merkava_4]

I disagree with everyone TallPaul disagrees with.

Did I say that right?

 

[Ramblin Fever]

I'm not sure what to think about which is best for seals.

I've had several vehicles all over 150-200k miles, only 3 have ever had rear main seal issues: an '85 Toyota 22re p/up that was 20yrs old before it developed a leak (can't complain at 20yrs of life), a '99 Chevy 6.0L Vortec V8 developed a leak around 80k miles (whole truck was an issue though) - both of these trucks ran Havoline 10w30 consecutively.

The 3rd vehicle, our current '01 Dodge Cummins diesel, running Delo 400 15w40 since our purchase of it 3yrs ago, developed a mild weep at around 70k or so - replaced under warranty.

I've had many other Isuzu's, Hyundai's, Chevy trucks, Datsun p/up, and a Honda car that all ran on Havoline regular oil, all over 160k/10yrs without any leaks, major gasket weeps.

Still have the current Isuzu with 173k miles now, ran Havoline dino for it's first 145k miles, then switched to GC for 1k miles (ran like #@$%! on it); has had different oils since then, i.e. Motorcraft blend, Valvoline Durablend, Maxlife regular, Maxlife synthetic, Rotella synthetic for the last 30k miles - I have no leaks/weeps on this engine at all, it's bone dry.

I've only once replaced the valve cover gaskets 5yrs ago.

 

[ThirdeYe]

I've had two leaks on my cars throughout the past 3 years or so that i've been driving. My first car I only kept for about 6 months and sold the thing because it was breaking down nonstop, but never had any engine troubles. My 2nd car, the 1998 Nissan Altima had a pretty decent sized leak from the valve cover gasket when I purchased it, and the oil change history was "unknown" but the engine ran perfect after getting that fixed, and when I changed the oil on it a week before I sold it, it had no sludge and looked great. Not sure what caused the leak in that case. In my car I have now, I had a slight weep from the Cam Plug but that's common for /all/ Integras and a lot of other Hondas. I'm thinking that perhaps it's partially to do with the weather and also the quality of the materials used to make the seals and bonding material in the first place. I'm not an expert though, just my 2 cents. All of those cars including the one I have now, ran on conventional.

 

[ryansride2017]

There is a big difference between seal "reconditioning" which Valvoline states and "seal swelling" which Frank states. If actual seal swelling occurred, and since I've used high mileage oils for 110K miles now, you would think my seals would be laying on the asphalt somewhere.