69 replies to this topic

[operose]

I once heard a myth on this board that said that synthetic oil will make a high mileage engine more prone to leaking oil...

I asked my dad about this because he's a reliablility engineer for the largest aluminum producer in the world, and has done more research on synthetic motor and gear oils than most of the people that produce/market/sell these oils.

this myth is NOT true.

any other questions about synthetic oil I'd be glad to pass on to him

[phishy75]

It makes sense. The amount that leaks should only be dependant on the viscosity of the oil you use. If anything, synthetic should leak less because it is less prone to viscosity breakdown over time and will not become thinner as it gets older. I've heard that myth plenty before, and always wondered about it's validity. Interesting tidbit...

[WJM]

synthetic is good. it is the only logical choice.

[archemitis]

i hate to disagree, as much as i love mobil1 but it deffinately makes my motor leak more than when im runing castrol of the same weight. its not a myth, if it happens to you. but im talking a few more drops per parking spot, nothing huge.

[83projectbrat]

my dads porsche 930 (911 turbo) with 13,000 miles on it leaked like crazy with synthetic, then we went back to the castrol gtx and no more leaking. the oil sits in the push rod tubes so it leaked. i saw that with my own eyes that synthetic made this car leak

[phishy75]

fair enough. I wouldn't know cause my motor with 230kms leaks maybe 10 drops between changes:grin:

I'm sure the little extra leakage is well worth the extra life you will get out of your motor though.

[edrach]

I switched over to synthetic (Amsoil 10W-30) with 130K on my '91 Legacy wagon. I did not experience any leaks; as a matter of fact my oil consumption decreased from 1 quart every 1500 miles to 1 quart every 5000 miles. I attribute this to the fact that the synthetic is less prone to "burning" off. On the other hand when I switched to synthetic on our '80 Toyota pickup at 120K, I noticed a fine layer of oil in the engine compartment within a month of the switchover. However, I don't see any actual leaks since I switched. I can't speak to an increase in oil consumption since I change the oil every May (about 3000 miles); this is our camper wagon which only gets used during the summer months.

[DerFahrer]

The only time I have ever seen my Legacy burn oil is when I was using partial synthetic oil. I was burning it at up to a quart a week if I pushed the car a bit. Switched to dino and stopped burning it completely, I did nothing else.

You all argue all you want. I know where I stand.

[rallyruss]

wow.... here we go again....

I have run both. never noticed any leaks. greater or lesser due to the oils. yeah leaks happen. just changing from one brand to another may contribute to leakage as different oil packages are not always compatible.

well I guess anything is possible. I had a guy tell me that the red line oil that we both used would cause my motor to leak. three cars later and still no leaks.

Im back to regular castrol due to the price of oil changes with the amount of miles the cars rack up. and delo 400 for the diesel benzo.

I do run an oil cooler and turbo timer to try and help out.

[BlueTrain]

Well, lets see. Some folks on here have had no leaks. Then after switching to synth, developed leaks. Therefore, this is not a myth. However, one also cannot make a blanket statement stating that switching to synth will definitely cause an oil leak, as some have made a switch and developed absolutely no leaks. This has been debated on many occasions on this site. I've come to the conclusion that it's kind of like russian roullette. Some may get a leak, some may not. Personally, i choose not to take that risk, and stick with dino. All of the vehicles ive seen make it to 250,000+ have been run on dino, changed on a regular basis. I personally run 10-30 Castrol GTX and Napa Gold filters. Works for me.

[Sweet82]

The myth can't be true!!

My car leaks all over the place and I have never used synthetic oil!!

Glenn,
82 SubaruHummer, always has clean oil (never stays long enough to get dirty)
01 Forester

[DerFahrer]

It depends on what's been replaced on the engine obviously.

If you've replaced oil seals (a lot of us do it ), let's say you've replaced the cam and crank seals from a timing belt change, or let's say you've done a clutch and replaced the rear main in the process, and let's sat you've done valve cover gaskets and the oil pan gasket... you're not gonna leak very much, if any, oil since you have all these new seals.

But my problem wasn't any of those seals, it was the valve guide seals apparently... :-\

[MorganM]

Ran regular dino oil in my 472 cadillac engine. At the time I had slow oil leaks. Over night I would leave a little puddle the size of a silver dollar.

Switched to Valvoline full synthetic. After switching I no longer left ANY drops on the pavement.

Go figure

[SubaRube]

The leaking comes from how well the syn cleans the engine. If your engine is full of crap, it might leak more after its cleaned out by the syn. And synthetics have seal conditioners in them to help this not be a big problem.
A guy at AMSOIL told me to use the their less-potent syn. I guess it doesn't have as harsh a cleaning additive in it. From what I know, alot of the rumors of leakage came from older syn's that didn't have the conditioners in 'em. And obviously, how good a condition your engine is in. Mileage isn't always a good way to determine the condition of the engine. How has it been treated throughout its life, ya know?

[Milemaker13]

Well, lets see. Some folks on here have had no leaks. Then after switching to synth, developed leaks. Therefore, this is not a myth. However, one also cannot make a blanket statement stating that switching to synth will definitely cause an oil leak, as some have made a switch and developed absolutely no leaks. This has been debated on many occasions on this site. I've come to the conclusion that it's kind of like russian roullette. Some may get a leak, some may not. Personally, i choose not to take that risk, and stick with dino. All of the vehicles ive seen make it to 250,000+ have been run on dino, changed on a regular basis. I personally run 10-30 Castrol GTX and Napa Gold filters. Works for me.

Phone's ringin' Dude!

[Loyale 2.7 Turbo]

I once heard a myth on this board that said that synthetic oil will make a high mileage engine more prone to leaking oil...

...this myth is NOT true.

Well... I just wanna Add that the Oil Doesn`t make any Damage to any Metal, so the Leaks come due to the Seals. Let me Explain:

Older engines came with the Seals Not Designed to Resist the Synth Oil, which damages the Seals as Bad Brake Fluid (With much Alcohol content) will Damage brake Seals...

When Synth oil first came, Sellers give a Li`l Paper Sheet, with the Warnin` About the Seals. so Older Engine will Leak with Synth Oil due to Seal Fail against Synth Oil.

Newer Cars come Prepared for it.

You all argue all you want. I know where I stand.

[nipper]

I once heard a myth on this board that said that synthetic oil will make a high mileage engine more prone to leaking oil...

I asked my dad about this because he's a reliablility engineer for the largest aluminum producer in the world, and has done more research on synthetic motor and gear oils than most of the people that produce/market/sell these oils.

this myth is NOT true.

any other questions about synthetic oil I'd be glad to pass on to him

It's a semi myth. It doesn't cause a good seal to leak, it just causes a weak seal to leak sooner. It's just a differnce between them leaking in 1000 miles or 5000 miles, but either way it was going to happen.
Seals may leak for a very short time after the changeover, but they usually stop, and its not enough to notice if the seals are good.

By the way, its usually safer to talk politics and religon then it is oil

nipper

[Milemaker13]

By the way, its usually safer to talk politics and religon then it is oil

nipper[/QUOTE]


Wow, that must be one HOT topic!!!

[jeffast]

i switched over to valvolinedurablend synthetic blend and the car runs a little better but with the way i drive it it has always burned a little oil, i havent noticed any increase or decrease since the switch i'm probably going full synthetic next change

[nipper]

[quote name='Milemaker13']By the way, its usually safer to talk politics and religon then it is oil

nipper[/quote]


Wow, that must be one HOT topic!!![/quote]

hehehe its been quite "colorful" in the new gen forums.

nipper

[jeffast]

have there been any threads with good info on which is better, or which one would you reccomend for a good laugh

[DaveT]

What I have gathered is that way back when the first attempts with synthetic were made, there were problems with the oil damaging seals. Somethin about the formulation, etc.. As far as I know, this wouldn't apply to current synthetics.


I have switched 3 high milage EA82s to synth. 1) 1978 1600 4x4 wagon. 1 loyale - my 1990 was switched when we bought it with 15K miles. I use the Amsoil bypass filter & air cleaner & engine filter also. NEVER changed the oil in that car. Only added ocasionally. Around 170K miles took the engine out to do a reseal. Checked some of the bearings, etc. All well in the standard sizes. Crosshatch still on cylender walls.

I don't baby the car. Big loads. Towing. 5-6K RPM getting on highway.

OK, you can have the same results with regular oil, 3K changes. But I didn't spend all the time and / or money to do them. I did the math back when, it doesn't take too long to break even on the cost / return on investment.

No problem with leaks. Some had leaks, some leaked eventually - years later, like they all do - 190+ degrees doesn't make the seals last forever. No burning oil problems.


Never had an engine failure - other than timing belts or electric related.

I also use the sythetic ATF & gear lube.

Only repair to the much maligned 3AT trasmissions in 4 cars has been the vacuume modulator.


Can you drive around for a week with regular oil and water mixed in the crank case? (50/50 by the end - long story, stupid oops) And the engine still runs good after new gaskets. Burns oil, but that was caused by the run-dry overheat that caused the coolant leak...

Just things that I have done / seen / experienced with 4 EA 82s over almost 20 years.

[Loyale 2.7 Turbo]

...when the first attempts with synthetic were made, there were problems with the oil damaging seals. Somethin about the formulation, etc.. As far as I know, this wouldn't apply to current synthetics...

Thanx for the Info! ... I didn`t knew that new Formula Synth oil doesn`t Damage seals.

[nipper]

have there been any threads with good info on which is better, or which one would you reccomend for a good laugh

Well there is the ever popular synthetic vs mineral oil blinker fluid debates.....

One thing people forget about synthetics (which doesnt apply to this board but as a refernce) is that oil filters still need to be changed at the recomended intervals, as dirt is dirt. Also if a mfg of a new car doesnt specify a differnt synthetic oil interval (if the car did not have syn in it new) then you still have to change it at the mfg interval to keep any warrenty in effect.
Even the Syn Oil Mfg state oil filters still need to be changed at the mfg regular interval. I think cost over the cars lifetime is the same either way. Syn is probably best for extreem conditions, but everyone else seems to make no differnce either way.

nipper

[DaBrizat]

Well, lets see. Some folks on here have had no leaks. Then after switching to synth, developed leaks. Therefore, this is not a myth. However, one also cannot make a blanket statement stating that switching to synth will definitely cause an oil leak, as some have made a switch and developed absolutely no leaks. This has been debated on many occasions on this site. I've come to the conclusion that it's kind of like russian roullette. Some may get a leak, some may not. Personally, i choose not to take that risk, and stick with dino. All of the vehicles ive seen make it to 250,000+ have been run on dino, changed on a regular basis. I personally run 10-30 Castrol GTX and Napa Gold filters. Works for me.

Curious about what you guys mean by "dino." Its natural oil, which comes from dead organic matter, like DINOsaurs, right? Is that why the natural oil is called dino? If so, that's kinda clever.

Just trying to keep my jargon and slang straight.

As for the oil sitch, I'm rollin dino, yo. And the leaks are abundant.