[Hosam]

Just wondering if you guys have tried any type of synthetic in ur high mileage 5M's. Did u find that it causes leaks?

 

[Supraa_luva]

In my original engine I used to use castrol syntec blend and I had already had an oil leak. When I started using it it leaked a bit more than usual. Used that till my engine blew from lack of oil. (sorta long story) Not quite blaming it on the oil as there were other factors involved, but could have added to the demise of my 5m-ge.

Now in the 6m-ge I had installed a few years ago I still use castrol syntec 10w-40. Havn't had any leaks at all with it but of course there are all brand new seals throughout the engine.

also I'm not the most car savvy guy around here so you might not want to listen to me.

 

[dan12771]

posted already

theirs been a few posts from people that have switched to synthetic and they said it did cause leaks so chance's are you wouldn't want to go synthetic with your high milage 5m.

 

[Andrew]

Synthetic on your high mileage 5M.. ROFLMAO... Don't make that big mistake, you'll wreck your engine. AFAIK petrolium based motor oil helps fill holes in your engine, and helps stop leaks. Switching to synthetic will flush all of that helpfull buildup in your engine, and cause leaks and oil consumption..

 

[Magnus]

Synthetic on your high mileage 5M.. ROFLMAO... Don't make that big mistake, you'll wreck your engine. AFAIK petrolium based motor oil helps fill holes in your engine, and helps stop leaks. Switching to synthetic will flush all of that helpfull buildup in your engine, and cause leaks and oil consumption..

So let's see.. there's holes in the engine (bad) and the oil builds up around it and stops it.. And this is a good thing? Helpfull buildup? SCuse me? I've never heard of buildup being GOOD for an engine. Matter of fact, engine flush is suppose to get rid of the build up.. Tell you what, you keep running the oil that causes build up in your engine, and I'll keep running synthetic.... Build up.. helpfull.... and all this time I thought that was bad......

 

[Magnus]

Re: posted already

theirs been a few posts from people that have switched to synthetic and they said it did cause leaks so chance's are you wouldn't want to go synthetic with your high milage 5m.

If your switching to synthetic and you see a leak, that's because the synthetic cleaned out the engine. Isn't that what a good oil is suppose to do? If I switch to a syn oil and see leaks, I'de fix the leaks, and keep running syn. Oh.. BTW this is from a guy that has switch 3 cars to syn, and not had a problem.

 

[Flyin' Hawaiian]

Okay, let's get it straight once more...
Dyno oil does not "build up", what it does is it tends to swell up all rubber seals in your engine, it's just something dyno oil does.
Synthetic oil does NOT allow rubber seals and gaskets to swell, so what happens to an engine that has been running dyno oil for years is it allows the seals/gaskets to shrink back to their normal size. Unfortunatley, once this happens, these rubber parts are unable to keep the oil from passing around themselves, which starts the leaking process.
If you have not run synthetic oil in your vehicle in the past 30~40k miles, I'd suggest not to change over. If you really feel you have to run synth, go with a blend first to see how it reacts to it. You'll know if its going to leak within a week of running the new oil. If you don't see any leaks or wet spots around the engine, then try going to full synth.
The good news is that, in most cases, if you do start getting leaking after changing over, you can simply go back to a good dyno oil and within about 2 weeks the seals will swell back up and stop the leaking.

 

[Magnus]

Okay, let's get it straight once more...
Dyno oil does not "build up", what it does is it tends to swell up all rubber seals in your engine, it's just something dyno oil does.
Synthetic oil does NOT allow rubber seals and gaskets to swell, so what happens to an engine that has been running dyno oil for years is it allows the seals/gaskets to shrink back to their normal size. Unfortunatley, once this happens, these rubber parts are unable to keep the oil from passing around themselves, which starts the leaking process.
If you have not run synthetic oil in your vehicle in the past 30~40k miles, I'd suggest not to change over. If you really feel you have to run synth, go with a blend first to see how it reacts to it. You'll know if its going to leak within a week of running the new oil. If you don't see any leaks or wet spots around the engine, then try going to full synth.
The good news is that, in most cases, if you do start getting leaking after changing over, you can simply go back to a good dyno oil and within about 2 weeks the seals will swell back up and stop the leaking.

Lets get it straight once more... I answered his post.. nothing more.. nothing less.. His logic was severly flawed, as even you can point out. Or maybe you missed the sarcasm?

 

[Speed Racer]

Okay, let's get it straight once more...
Dyno oil does not "build up", what it does is it tends to swell up all rubber seals in your engine, it's just something dyno oil does.
Synthetic oil does NOT allow rubber seals and gaskets to swell, so what happens to an engine that has been running dyno oil for years is it allows the seals/gaskets to shrink back to their normal size. Unfortunatley, once this happens, these rubber parts are unable to keep the oil from passing around themselves, which starts the leaking process.
If you have not run synthetic oil in your vehicle in the past 30~40k miles, I'd suggest not to change over. If you really feel you have to run synth, go with a blend first to see how it reacts to it. You'll know if its going to leak within a week of running the new oil. If you don't see any leaks or wet spots around the engine, then try going to full synth.
The good news is that, in most cases, if you do start getting leaking after changing over, you can simply go back to a good dyno oil and within about 2 weeks the seals will swell back up and stop the leaking.

Lets get it straight once more... I answered his post.. nothing more.. nothing less.. His logic was severly flawed, as even you can point out. Or maybe you missed the sarcasm?

Uh guys...

I sense tension in this last post. Relax.

Both of you are right in your own way - each of you have good points and you're correct about the effects of synthetic oil in a high mileage engine. I can see the SUPRAFORUMS-ness in this thread...and I'm hoping it's not going to go much further.

Anyways, I'm considering running Amsoil in my 5MGE - and it has 137,000 miles on it. Now I'm having misgivings about doing this. Hmmmm.

 

[Black Dawg]

If you're not turbo, or highly built, and run regularly at high RPMs, synthetic is just not necessary and just an extra cost. On a turbo engine, it is all but a necessity, on a high milage stocker, just run petrol, you'll be fine. I feel high milage engines need regular oil changes, and that gets expensive real quick with synthetic. Just my $0.02

 

[Magnus]

If you're not turbo, or highly built, and run regularly at high RPMs, synthetic is just not necessary and just an extra cost. On a turbo engine, it is all but a necessity, on a high milage stocker, just run petrol, you'll be fine. I feel high milage engines need regular oil changes, and that gets expensive real quick with synthetic. Just my $0.02

That's cool, everyone is entitled to thier opinion. (And we all know about opinions LOL ) I've been using syn oil in 4 of my cars over the last 10 years. I like the way it comes out cleaner, I like not having to change the oil for 5000 miles instead of 3000. I like the way my cars run when I have syn oil in. 2 of those cars were high mileage, ran petrol before. Both of them were quieter under the syn oil. I guess that's why I get so defensive at times, I love the stuff almost as much as I love my MKII. (Which has had syn oil in it from birth.)

 

[Black Dawg]

That's cool, everyone is entitled to thier opinion. (And we all know about opinions LOL ) I've been using syn oil in 4 of my cars over the last 10 years. I like the way it comes out cleaner, I like not having to change the oil for 5000 miles instead of 3000. I like the way my cars run when I have syn oil in. 2 of those cars were high mileage, ran petrol before. Both of them were quieter under the syn oil. I guess that's why I get so defensive at times, I love the stuff almost as much as I love my MKII. (Which has had syn oil in it from birth.)

to each, his own..... :wink:

 

[TEMPEST]

I use synthetic in all my cars. If I develope a leak I had a problem I didn't know about..and I fix it. I do not necessarily like the idea of built up fats, funguses, silts, sludge etc plugging up my engine. Not only leak spots, but journals, bearings etc that would not receive proper lubrication when plugged up. I guess I cannot deny that paper gaskets swell with mineral oils, but there arent many benefits of that to me. you'd still be hiding a problem. But I've never been the duct tape and bailing wire fixer upper either. In my line of work that makes for a one way trip, and I ain't explaining to anyones wife why their man aint comin' home. The quality of maintenance just filtered to my own stuff. Hell I don't even like the dealer fixin' my cars..they don't clean anything!
Mineral based oils suffice just fine and will get'cha by, but I can do better so I do. Synthetic oils are superior in all heat dissipation, lubrication, and cleaning. That's what I buy an oil for.
TEMPEST

 

[BACK2SUPRA]

Running Sythetic - No Problem

Purchased 86' MK2 with 91K. Owner used dyno exclusivly. Friend of mine informed me of a product called AutoRX. Tried it as directed (two applications). Was very skeptical at first. He installed it on his 98' Sienna (known to have sludge problems). Installed Mobile 1 15W30 (wanted a slightly thicker oil, just in case) and had no such problems with leaking whatsoever. Has been 3K so far without a problem.
Just my $0.02
Al

 

[Dave A.]

Well, considering that synthetic oil was first developed for use in jet engines, I don't think there's much doubt that good synthetics can keep deposit build-up down to a bare minimum. :wink: The very first synthetic oil developed for automotive engines was also pioneered by a jet fighter pilot.