GC 0w30 in 3800SC

quote:
Originally posted by 98RegalGS: Could I use GC 0w-30 even though my engine specs for 10w-30? A 0w is a bit thinner, correct? Couldnt I get blowby running that oil? Or maybe IM misunderstanding the numbers.
0w-30, 5w-30, and 10w-30 are all 30 wt oils at 212F. The 0w, 5w, and 10w only refers to the pumpability at 0 degrees. When your engine is warmed up, 0w-30 is still a 30 wt regardless of ambient temps. It will work the same in Florida as it would in Alaska. The german version of Castrol Syntec 0w-30 is significantly thicker than Mobil1 0w-30 and almost as thick as Mobil1 0w-40 Look around here a bit and you'll understand that some Xw-30's are closer to 20 wt oils while others are almost 40 wt oils. GC is one of those that is almost a 40 wt.
 
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Here are some viscosity numbers in cSt, at common start-up temps, to illustrate what Dr T, Haley & Medic are talking about:
code:
TEMP		GC	Amsoil
C	F	0W-30	10W-30
0	32	545	592
5	41	394	423
10	50	292	310
15	59	220	231
20	68	169	176

  

The Amsoil 10W-30 is 11.9 cSt @ 100C and GC is 12.1 @ 100C, so both are on the thicker end of the 30 weight scale. So the start-up viscosity will be very similar at temps of 32 degrees F or higher. [Smile]
 
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Thanks for the #'s Blue. Yeah, if my GC supply ever dries up and I can't get it for $3.99 anymore, the ATM is probably what I'll go with. Around 12 cst is nice. [Happy] Not too many selections in that range, thanks to starburst.
 
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Thanks for the info [Smile] Definitely learned something today [Smile] Looks like Ill send this UOA in on Amsoil this spring and try out some German Castrol!
 
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quote:
Originally posted by 98RegalGS: Thanks for the info [Smile] Definitely learned something today [Smile] Looks like Ill send this UOA in on Amsoil this spring and try out some German Castrol!
Look forward to your uoa, maybe I'll have my GC one in around May. Then I'll run the Amsoil out.
 
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I keep hearing everyone praise the GC 0w-30, how good it protects the valvetrain, etc. Now heres my dilemma. Could I use GC 0w-30 even though my engine specs for 10w-30? A 0w is a bit thinner, correct? Couldnt I get blowby running that oil? Or maybe IM misunderstanding the numbers. I currently run Amsoil 10w-30.
 
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You can use any oil in any engine depending on outside ambient temperature. That said, yes you can use GC 0-30 in your Buick in lieu of a 10-30. However, if you're using Amsoil, then I can't see GC being too much (if any) of a better lube. The 0W will allow you to start down to -40C. It's won't be too much thinner (if any at all) during the rest of the temperature range over a 10W-30.
 
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GC 0W-30 is actually a bit thicker at 100°C than the Amsoil 10W-30 when new. It's not too thin. Either oil is a good choice. Both would seem to be an ideal for this engine. I'm running GC in my 2000 LS for now, also have ATM 10W-30 on the shelf. Both are at the high end of the 30wt. range. The 10W-30 ATM actually has better Winter performance than the 10W implies. Don't think anyone can say that one is any better than the other as far as wear #'s and not-too-extended oci's. I'd sure like to see some comparisons in the LS1 type engines between these two. [ March 07, 2005, 01:03 PM: Message edited by: haley10 ]
 
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I have a 97.5 Regal GS (SC) and I'm running 0 weight in it right now (M1 not GC) with no ill effects. It's still pretty cold here in Michigan and I thought 0w would flow better. Would like to see what your UOAs turn out to be.
 
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I had a Regal 3800 Turbo in 1979-81...oh, if only I had GC back then...and if only I had taken it when I moved to Germany instead of trading it because the Buick dealer said they wouldn't be able to work on the turbo motor in Europe...I should have known better!!!! [Frown]
 
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