Damage to gaskets by switching to syn. oil.

[lavapearl]

I was told by a mechanic that it's ok to switch to syn. oil for a newer car with low mileage but if your thinking doing to the same to an older car with let say 80 000 + miles you will damage the gaskets.

[Joe K. 99 Zeee!!]

It shouldn't damage gaskets. Some people have reported leaks after changing over, and that's probably where he got that idea. The fact is those gaskets were already damaged. Synthetic oil is just doing what it does best...flowing into places that normal oil wouldn't

[Rob B (shoebox)]

Some mechanics shouldn't be... well... mechanics.

[Dragkid1917]

Its generally said that an older engine should be given thicker oil just to protect it, and the thicker oil wont leak outof gaskets, and thought it will create a drag on the crank it will protect very well. Synthetic oil is thin and has the possibility of seeping through little cranks and crevices that and older engine might have, overall its not a problem and the only think that would ever go wrong is seizing up for some unknown reason and that really doesnt happen if u have the correct amount of oil. Just get a new filter, drain the other oil alllllll out and put the synthetic in the new filter and then engine and you will be fine.

[Steel2686]

Just agreeing with Joe and Rob. Synthetic oil has no properties that would result in damaged gaskets. 1,000 miles or 100,000 miles... Switching to a synthetic oil like Mobil 1 is a smart move.

I can vouch for it. I bought my daily driver a little over a year ago. It had 115,000 on the clock. I immediately did an oil change with Mobil 1 and not a single issue. I know the previous owner, and he used regular Pennzoil for it's entire life leading up to when I bought it.

[fastTa]

There were some very minor problems with some of the cheaper synthetic oils years back with seal swelling and very poor detergent packs.

But with today's additive packs, there is absolutely no problem with synthetic oil and gaskets.

[dochidalgo]

I've read the synthetic oil has molecules smaller than organic oils, so if the gasket is not mounted well or is damaged for any cause, the synthetic oil will leak...otherwise is the best lubricant you can add to your engine and tranny
Dochidalgo

[01Z]

Don't know about the molecule size but the shape is different from mineral oil. Round vs oval. I'm looking at one now.

[Injuneer]

Conventional oils gain their multi-viscosity properties from "viscosity extenders". These are vary large, heavy, long-chain molecules that expand and contract with temperature to vary the viscosity. In this respect, the converntional oil molecules are larger. But it is these long-chain molecules that are damaged by heat and mechanical shearing, breaking down and causing converntional oils to lose their viscostiy properties. Synthetics are very uniform "designer" molecules that gain their viscosity properties in other ways, and are less prone to breakdown from heat and shearing loads.