I'm a religous M-1 user, but I've heard the GC 5W30 is actually closer to a 40W, and the M1 is barely 30W. I can't find the GC in Wichita Falls, is the Made in the US stuff the same? If it isn't then what's the big difference. Thanks in advance for any replies.
Whats the difference between GC and regular syntec from the US?
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GC is a "true" synthetic base stock oil.
Syntec is a group III base stock oil ( severly hydrocracked dino ).
Syntec is a group III base stock oil ( severly hydrocracked dino ).
What's the difference between GC and regular Syntec from the US?
Elves!
Elves!
It wouldn't suprise me one bit if the US Made Syntec has more then just group iii as the basestock. You can counter argue that the majority of the base is group 3, and I would agree with you. I just would be willing to put money on the fact there is more to it then just group 3.
No not really. GC is 12.1 cst @ 100C. Your 10W-40's start out at 13.7 cst @ 100C and go up to 15.7 cst @ 100C. GC is very close to High Mileage GTX 10w30 in viscosity.
Patman
Staff member
Actually, the cutoff point for 40 weight oil is 12.5 cst, so GC is most definitely almost a 40 weight oil since it comes in only a few points below that. The VOA I have on GC shows it at 12.2 cst. And in my car it usually thickens up a tiny bit and gets even closer to being a 40wt with more miles.
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I think Clyde meant that most 10w-40 start well into the 40 range and aren't on the fringe of the lower limit. That is, none are typically 12.6 that have the 10w-40 label.
Still ..GC is close to the 40 threshold.
Still ..GC is close to the 40 threshold.
When you say cutoff, do you mean the beginning of a 40 weight? Is there a 10W-40 that is as thin as 12.5 cst @ 100C ? If so, please list it because I am curious to hear about it.
this chart help?
www.texacoxpresslube.com/carcare/article_viscosity.html
How about this one?
www.bobistheoilguy.com/visc.html
www.texacoxpresslube.com/carcare/article_viscosity.html
How about this one?
www.bobistheoilguy.com/visc.html
www.texacoxpresslube.com/carcare/article_viscosity.html
Yeah that one spells it out quite nicely.
I had no idea that a 40W starts out at 12.5 cst @ 100C.
Patman
Staff member
You won't find a conventional 10w40 that starts out that low for one simple reason. Most (if not all) conventional 10w40 oils will thin out very easily, so if they started out at only 12.5 cst, they would become 10w30 within the first 1000 miles.quote:
Originally posted by Clyde65:
When you say cutoff, do you mean the beginning of a 40 weight? Is there a 10W-40 that is as thin as 12.5 cst @ 100C ? If so, please list it because I am curious to hear about it.
But my basic point is, 12.5 is the bottom point for where an oil is classified as a 40 weight, so when the original poster said that GC is closer to being a 40 weight oil, technically he is absolutely correct.
So that's why I never cared for Keebler baked goods... (Little poops're usin' motor oil instead o' shortening! Blechh !
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