I have heard it said that synthetic lubricants will seep and/or leak past a seal where conventional lubricants will not. I don't know the accuracy of that statement. I just recently had a output shaft seal start leaking on my 03 r with 20,000 miles. I went to synthetic in the gearbox at 12k.
Anyone have any information on this subject?
Wayne
Does synthetic oil cause leaks?
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towerworker
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Synthetic Oil
Yes, in my experience synthetic oil can cause leaks. If you have an older engine/seal/gasket and shift to synthetic, it can cause leaks. Reason, as it was explained to me, was that synthetic oil has different absorption qualities than natural oils. Different synthetic oil manufacturers have different additives to attempt to mirror oil absorption into gaskets to keep them plump and sealing in your engine. If the switch to snythetic was done early enough in a gaskets life it shouldn't be a problem or using a synthetic oil that has good absorption qualities should eliminate problems.
I shifted to synthetic transmission fluid on an older vehicle and ended up replacing seals because the synthetic fluid actually ended up running out of the tranny.
I shifted to synthetic transmission fluid on an older vehicle and ended up replacing seals because the synthetic fluid actually ended up running out of the tranny.
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DJ Downunder
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In our bikes?...No...IMHODoes synthetic oil cause leaks?
But put it in an old bike and it might...here's why.
With new good synthetic oils the oil does three things....1 lubs..2 cools..3 cleans.
It's the cleaning bit that might case a leak in an old bike.
Old bikes sometimes have carbon and gunk build ups around joins and seals...clean this gunk away and oil can seep out of a bad seal.
DJ
Synthetics
The difference between Dino oil and syn oil was explained to me a number of years ago by the now deceased owner of Golden Spectro Oil. Dino oil has molecules of different sizes. This allows, in certain cases, the seals in older bikes to remain sealed,because the larger molecules block the leakage of smaller ones through the seals. Also, in older engines with a lot of wear
the smaller molecules get past the piston rings via scratches on the cylinder walls and then enter the combustion chamber resulting in oil consumption. In Synthetic oil, the molecules are engineered to be the same size. So, sometimes the molecules in syn oil may be small enough to allow seepage in gaskets,ie. they are too small to seal the gasket. On the other hand, the sny engineered molecules are usually large enough to prevent themselves from getting past the piston rings in said high mileage motors., thus resulting in decreased oil consumption. Who knows? Sounded good to me at the time
the smaller molecules get past the piston rings via scratches on the cylinder walls and then enter the combustion chamber resulting in oil consumption. In Synthetic oil, the molecules are engineered to be the same size. So, sometimes the molecules in syn oil may be small enough to allow seepage in gaskets,ie. they are too small to seal the gasket. On the other hand, the sny engineered molecules are usually large enough to prevent themselves from getting past the piston rings in said high mileage motors., thus resulting in decreased oil consumption. Who knows? Sounded good to me at the time
I have met the enemy, and he is us.
NO - It doesn't 'cause' leaks. YES - You may find things leak that didn't leak before because synthetic oils generally have a higher viscosity (flows better and is 'thinner') than many mineral oils. Lubricates better (arguable) than mineral oil, and also makes the engine seem 'noisier' mechanically as it has (again, arguable) lower noise damping properties (due to the higher viscosity).
This topic has a habit of cropping up every six months or so in different guises and generates a huge number of posts and opinions. For interest, I switched to synthetic at the 30,000 km mark and my bike stopped using oil with the change. On my round Aus trip (almost 16,000 kms with no service), I used so little oil that it didn't need topping up. The engine however, is definitely noisier and the left cam chain tensioner definitely rattles more with synthetic than with mineral oil.
This topic has a habit of cropping up every six months or so in different guises and generates a huge number of posts and opinions. For interest, I switched to synthetic at the 30,000 km mark and my bike stopped using oil with the change. On my round Aus trip (almost 16,000 kms with no service), I used so little oil that it didn't need topping up. The engine however, is definitely noisier and the left cam chain tensioner definitely rattles more with synthetic than with mineral oil.
I ride an R1150GS Adventure with sidecar. IBA #39193
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dwayne
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Re: Synthetic Oil
Actually what is happening is that the sludge that was left ny the conventional motor oil eats away at gaskets, then when you put in synthetic, it eats away at the sludge. So really what caused the leak was the old oil, the synthetic was just doing its job. The point; don't wait too long before switching to synthetic, and make sure it is indeed synthetic, not that crap that Castrol makes...its not really synthetic oil.gbq wrote:Yes, in my experience synthetic oil can cause leaks. ....
'05 R 1150 R Dark Ferro, with blacked out motor Member # 507
Does synthetic oil make your engine leak?
NO! 
Member #296
"Time flies like an arrow....fruit flies like a banana." Groucho Marx
"Time flies like an arrow....fruit flies like a banana." Groucho Marx
What MIXR said is it in a nut shell,
low viscosty = thick oil,
high viscosity = thin oil.
That applies whether it be synthetic or mineral oil.
Viscosity is the single biggest factor of concideration when selecting oils.
I'm gonna stop now before I get tooo carried away.I've seen this subject go on for pages' so, thanks and good night.
low viscosty = thick oil,
high viscosity = thin oil.
That applies whether it be synthetic or mineral oil.
Viscosity is the single biggest factor of concideration when selecting oils.
I'm gonna stop now before I get tooo carried away.I've seen this subject go on for pages' so, thanks and good night.