I'm totally with Loren on this issue - EXCEPT - Mobil 1 has been around since at least 1975 or so. An all metal silver can that you needed to punch or use a can opener! Guess is they (synthetics) were around even longer but it was Mobil that pushed it with intense advertising and initially wild claims of 25,000 mile change intervals! That didn't work out - they got in big trouble with that claim.
Have tried the Slick 50 and thought I noticed a change but can't prove it as I've always used synthetic oils. I forget what that stuff costs but I doubt it's a replacement for synthetic over conventional oil nor makes up the price difference. I swear the minor but real improvement in flow and less friction of synthetics make it cheaper in the long run by some fuel savings.
IMO the #1 advantage of synthetics is tolerance of high heat and lack of making sludge even when overworked.
In short - I don't think the Slick 50 hurts anything but probably isn't any better than common sense care and routine changes,
T
Ps + BTW - Amsoil is a site sponsor and I/we are not obligated but it is top quality without excuses - again in my opinion....
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Tom Greenleaf - MetroWest, Boston