<blockquote id="quote"><font size="1" face="Century Gothic, Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote"><i>Originally posted by GSCReno</i>
I have used Castrol GTX for 25 years without an oil related failure. Although I'm sure that some of our Canadian friends will dispute this, keep in mind that some will argue anything. Oil brands, production numbers, etc. Maybe I should wait until I've posted 9500 times to have an opinion... Cheers, Scott
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hmmmmmm I'll dispute the fact that there are no Canadians here with 9500 posts [;)]
(guess that what you are really referring to would be the fact that 20/50 wouldn't work very well with our cold temps eh???)
I'm on gtx 20w50 since forever and have often used my car until November without any real starting problems other than maybe a longer crank to moove the thick oil.......and honestly don't think there's many (if any) that use their cars in real winter conditions where the 20/50 would have the consistancy of molasses (ie -20 or lower) ....
With that covered,the issue of modern synthetics breaking down seals is false, they have be greatly modified over the years, and the seal swell rate for the major brands is now on par with other mineral based oils.
NB, but note that synths do have detergents that could possibly wash away some of the gunk in the engine that perhaps used to seal the dino-oiled areas...............
Some very outspoken and experienced experts (ie Ray Bohacz, who just recently wrote an article in Hemmings on exactly this kind of subject) have mentioned that on a properly rebuilt late model engine (our 70's tech engines could fall into this category), you could opt to use a 10w40 true synthetic, instead of the classic mineral 20-50 with no ill effects......and therefore benefit with the cold start protection, and less heat robbing friction, that a true quality synthetic offers.......
(for arguments sake, I'm still considering making the switch )
Ron.


