Do Synthetic Oils Cause Leaks?
No they do not! Many of the world's largest auto manufacturers require the use of synthetic oils as "factory fill" including Porsche and Mercedes. Even GM requires it in certain vehicles such as the Corvette.
So what's going on? Why the stories about the guy who put synthetic oil in his car after having no engine oil leaks running for perhaps several years using petroleum oil. Then all of a sudden he finds drips after a few weeks. Here's what's going on.
Synthetic oil flows more readily than petroleum oil does so if you have a leak it will tend to leak from it more freely. This however is caused by an all ready failing seal. Not by the synthetic oil itself.
Petroleum motor oils are notorious for forming what's know as a "false seal" Varnish and crud will build up around a failing seal over time and help keep a more viscous petroleum oil from leaking. Synthetic oils that are highly detergent will clean off the build up and expose the all ready failing seal. There's your leak!
For this reason I suggest that synthetic oil's only be used in mechanically sound engines. If you have a leaking seal replace it prior to installing synthetic motor oil.
I have also seen many cases where older engines are starting to seep oil because some motor oils have poor long term seal compatibility. Exposure to these low grade oils causes the seals to harden and seal poorly.
All motor oil, synthetic and petroleum alike contain chemicals as part of the additives that are added to the oil that are there to keep engine seals pliable and to cause mild swelling so the seal works properly. Some oils are better at this function then others. Another reason cheap motor oil is no bargain in the long run!
The additive's in Amsoil's synthetic motor oils are so good at conditioning engine seals that there have been many cases where engines with slight oil seeps sealed back up after a few thousand miles of driving. That being said if the seal is shot all you can do is get it fixed; no oil will fix it, synthetic Included.
Amsoil Inc developed the first full synthetic motor oil in 1972 to achieve American Petroleum Institute certification and today is considered the world leader in synthetic motor oils and lubrication.
By Larry Crider CLS, Amsoil direct jobber.