Do synblends cause leaks?

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We know switching to a full syn in an older vehicle can unveil leaky gaskets that were dammed up with sludge prior, and that the hydrocracked/synthetic molecules are smaller than in conventionals which also adds fuel to the fire.

My question is, will a syn blend cause this too? I'm considering switching to GTX SynBlend in an oil burner 1ZZ Corolla to slow the burning a bit. I have tried M1 in it in the past and had horrible results and do not want to go the full syn route again. Considering GTX SynBlend is probably only about 30% syn or so, could is possibly cause leaking? Car currently does not leak.

Castrol's site says, "GTX SynBlend cools critical engine parts providing a superior level of protection against wear and oil burn-off" and also "A higher level of thermal stability vs. conventional oils" and "Maximum viscosity and oil burn-off protection".
 
Originally Posted By: Doublehaul
I would switch "we know" to "I think".


I wouldn't. It's a pretty known issue. Doesn't happen in every case but happens enough to be a factor.
 
Don't think it would leak...though it might burn it faster.....


What about a cheap high mileage oil?
 
Originally Posted By: snowflake
I've used syns in a lot of older vehicles, none caused leaks or excessive burn off.


I ran one OCI of M1 5w-30 in this car a few years ago and it burned at a RAPID pace. Faster than conventionals like GTX and VWB. I know people say to keep running syn for a few OCIs and it should go back to normal but I'm not interested in burning money on oil like that. Castrol's wording has piqued my interest about SynBlends though.
 
Originally Posted By: daves87rs
Don't think it would leak...though it might burn it faster.....


What about a cheap high mileage oil?


Regarding faster burn off with syn content, why is this? Like I said in my last post, M1 burned FAST in this engine. So is a syn blend going to go quick too? It sounds better on paper but why does the opposite occur in reality?

I could try an HM but always associated them more with leaking gaskets and valve stems.
 
Originally Posted By: cheesepuffs
Originally Posted By: snowflake
I've used syns in a lot of older vehicles, none caused leaks or excessive burn off.


I ran one OCI of M1 5w-30 in this car a few years ago and it burned at a RAPID pace. Faster than conventionals like GTX and VWB. I know people say to keep running syn for a few OCIs and it should go back to normal but I'm not interested in burning money on oil like that. Castrol's wording has piqued my interest about SynBlends though.

Thats interesting, I'm not saying you didn't experience what you did, but its interesting because it contrasts as the opposite to mine.

The amigo runs smoother on syn with no burn off between oil changes (5k oci)

The F150 burns 1 qt every 1k regardless of whats in it.
 
Nope, synthetic and syn blends don't cause leaks. But they do clean, and remove sludge deposits that formed around seals. When seals are.kept away from the flow of oil by sludge, they harden. When exposed by the cleaning, they leak for a short time until properly softened up by the oil....as long as they are not too far gone.

I have changed vehicles with up to 105000 miles over from dino to synthetic. The higher the mileage the longer they leaked, but all tightened up within 3000 miles or so and were then leak free for as long as I owned them.
 
Originally Posted By: cheesepuffs
Castrol's wording has piqued my interest about SynBlends though.


I think you are reading too much into castrol's marketing buzz words. They are no more special than any of the other well known oil companies. Can a syn-blend cause a leak if it cleans crud off a old gasket? Sure, but so could any high detergent conventional/syn/syn-blend, depending on the condition of said gasket.

I will say, when I had my 2003 Buick century that was ran on conventional whatever Wal-Mart put in it for 170k miles at intervals that were probably unresponsibly long it never leaked. When I started actually taking care of my own car I started using maxlife syn blend, a few days after maxlife the oil pan gasket started leaking like crazy. 3000 miles later it stopped for good, until I got rid of the car.

So, if leaking is your concern and you still want to use a syn blend I would highly recommend one of the high mileage syn blends.. valvoline maxlife, Quaker state defy, and I believe castrols high mileage oil are all syn-blends.
 
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What you need is a HM oil like Maxlife, Defy, or the like. M1 HM works well, but costs too much if you have an oil burner. Forget about plain syn-blend for oil burning. It's a marketing term and some HM oils are already semi-syn. I know for sure Maxlife is a syn-blend. If you buy a couple 5 qt bottles at Walmart you will have a few spare qts to add along the way.
 
Originally Posted By: actionstan
Originally Posted By: cheesepuffs
Castrol's wording has piqued my interest about SynBlends though.


I think you are reading too much into castrol's marketing buzz words.
This.

Originally Posted By: actionstan
Can a syn-blend cause a leak if it cleans crud off a old gasket? Sure, but so could any high detergent conventional/syn/syn-blend, depending on the condition of said gasket.
And this.
 
I have had good results with Maxlife in my truck whichhas a small rear main leak
Maxllife has slowed the leak down
I am impressed with it
 
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