Originally posted by AliasJerk:
You really only get the benefits of a synthetic oil if you use it right from the start of an engine's life. You also risk damaging the seals on your engine by making the switch to synthetic
It's amazing how these old wives tales won't die...
Any motor in sound working condition can be switched to synthetic at any time. As soon as you switch, you begin to accrue the benefits of better flow at very low temps, resistance to oxidation at high temps, and generally better additive packs. As far as damaging the seals, that issue was solved back in the late '70s. It IS possible that some small leaks can occur when switching to synthetic in a motor that was poorly maintained and has a buildup of sludge and/or has seals which are hardened. When the better detergents and dispersants in the synthetic oil begin to clean away the crap that was plugging the seal, there can be temporary leakage until the seal conditioners restore the seal's pliability, then the leaks will stop.
I will admit that there's no real economic incentive to use synthetic oil unless you take advantage of its ability to go longer between oil changes. Using a $5.50/qt oil for 3,000-mile oil changes doesn't make financial sense, although you do still get the advantages listed above.
'99 'Tour (actually my brother-in-law's, but I'm the family wrench)
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