0w/30 and 10/30 ....which provides better strart up protection in mid-range temps

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May 9, 2003
Fayetteville, NC
while it's obvious that a 0w/30 provides better flow and thus protection during the start up and initial drive phases than a 10/30, I was wondering about the follwing: if one compared a 0/30 and a 10w/30 with similar Cst numbers at 100c(212F), they have the same thicknes when the oil is warm..ok (for instance GC and Pennz.HM 10/30). But how about warmer start up tepms, in "mid" range? for instance, which oil would protect better during start-up and initial drive phase at tamps about 50-60F? would the 0w/30 be too "thin" for summer starts? would a 10w be better for a motor during the summer for start-up, UNTIL oil reaches its highest visc? in other words: would the very good cold-flow capacities(low visc. at low tepms) of a 0w-30 be a DISadvantage during start-up at HIGH temps, cause its thinner than it "needs" to be at start-up? (sorry if this point is stupid..just wondering) Thanks for any educating answers.
97tbird, you're point is NOT stupid, it's a very good question! I doubt it makes ANY difference in wear in using a 0w-30 vs 10w-30 of the same formulation. The 0w-30, given that it's only really available in "true" synth form, is a top notch formulation that can be used in Montana in January or Houston in August, it fits the bill in both environments. The only real gains 0w offers are fuel efficiency when it's cold, 0w will win everytime and extended drains. 10w-30 dino is the way to go 'round these parts from April til November. (I like to run even thicker oils in the hot summers [Smile] ) For synth, 0w-30 will protect just fine, even when it's 90+F every day for months on end...
Thanks for the input from all of you; although I know I can use a 10/30 here in summer, I really might use the GC that I have now(UOA in a month at 3k miles), because it's thicker than a regular 0w/30, and I like that: it has the same thickness of Pennz.HM 10/30 at 100C. If the UOA is REALLY bad, I might try the Pennz.HM 10/30 or: if the uoa is sort of OK, give the GC another try, dpending on HOW it looks. But mostly I hope the GC uoa in my T-bird will be good, and that the little consumption I have with it now(about 1/2 qt.per 3k miles) decreases/stops with the 2nd run. Thanks again.
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