GC too thick for normal winter temps?

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I've been mostly using GC for the last four years in my
328i. I'm starting to use my car year round now and I know
that GC is thicker than most 5w30 oil's so wouldn't a 5w30
oil be better to use in normal winter temps? I have a small
stash of 5w30 Valvoline Maxlife Synthetic. I know the 0w
rating is great if it's -40 but what about at 0 to -18 celsius
(32 to -5 deg F) temps?
 
It's thicker at temp, but not in the cold.

My dad (2002 540) and I (1998 528) have been running GC all winter for years with excellent UOAs. UOAs were good on M1 0W40 too, but I prefer GC for various reasons.
 
Originally Posted By: Craig in Canada
It's thicker at temp, but not in the cold.

My dad (2002 540) and I (1998 528) have been running GC all winter for years with excellent UOAs. UOAs were good on M1 0W40 too, but I prefer GC for various reasons.


Wrong. GC is thicker at "normal" winter temps than most synthetic 5W-30's. At extreme cold temps (-40)the GC will flow a little better than a 5W. That being said I have run GC for about 5 winters now with no cold crank issues.
 
Ktm_525. Thats what I think. GC is thicker, but does anyone
know how thick it is? Is it thicker than a mineral 5w30/10w30
oil or 10w30 synthetic? If it is thicker, why use it then.
 
GC in my Toyota has never given me a problem in five Chicago winters. Car is used as a commuter with outside parking and two cold starts per day. No noise, no hard cranking.
 
Originally Posted By: 2KBMW
Ktm_525. Thats what I think. GC is thicker, but does anyone
know how thick it is? Is it thicker than a mineral 5w30/10w30
oil or 10w30 synthetic? If it is thicker, why use it then.

My guess is that you get the best of both worlds. Thin for start up protection and alittle thicker for operating temps. I use it in the wifes 97 Jetta great stuff.
 
Even if it's thicker by the crude kinematic measures that underpin the rating on the bottle, it can still pump and flow better in the important parts of the engine.

Either way, the difference will be minimal, and certainly nothing compared with the other aspects of GC's formulation (shear stability, anti-wear, deposit control, etc.).
 
I agree. Even though GC is a "little" more thick than a syn 5W-30 in semi cold temps (-5 to -25C) it still flows easy. Last winter at -25 GC poured fast from the bottle. Good enough for me.
 
@2KBMW:

Everyone needs to remember that your engine still needs its favoured characteristics once it's warmed up too. I don't care if GC is a "little" thicker in some bracket of moderate temperatures. GC is great in the extreme cold (ie. -40C), and it's the proper heavy-30/light-40 ACEA A3 weight my engine (yours too, guessing from "2KBMW") needs when its warmed up. I don't think Maxlife lives up to those standards.

Engines only need oil when they're running (duh) and unless your habits are quite severe a *typical* engine still spends most of the time it's running at proper operating temperature not at 0C.

GC is thin enough at 0C to earn a 0W rating - good enough for me.
As I said, GC and M1 0W40 both gave me excellent winter UOAs. I don't believe anyone has seen data from Castrol to give a full viscosity curve from -40C to 125C, but I thought that someone at one time had interpolated one from their own observations. I don't have a link.
 
Originally Posted By: Craig in Canada
GC is thin enough at 0C to earn a 0W rating

I don't think 0W rating is measured at 0C.
 
Originally Posted By: Craig in Canada
@2KBMW:

Everyone needs to remember that your engine still needs its favoured characteristics once it's warmed up too. I don't care if GC is a "little" thicker in some bracket of moderate temperatures. GC is great in the extreme cold (ie. -40C), and it's the proper heavy-30/light-40 ACEA A3 weight my engine (yours too, guessing from "2KBMW") needs when its warmed up. I don't think Maxlife lives up to those standards.

Engines only need oil when they're running (duh) and unless your habits are quite severe a *typical* engine still spends most of the time it's running at proper operating temperature not at 0C.

GC is thin enough at 0C to earn a 0W rating - good enough for me.
As I said, GC and M1 0W40 both gave me excellent winter UOAs. I don't believe anyone has seen data from Castrol to give a full viscosity curve from -40C to 125C, but I thought that someone at one time had interpolated one from their own observations. I don't have a link.




I remember this curve too, it wasn't linear and the difference was slight compared to the 5w's. I have no idea where the 0W rating temp is but I have noticed that 0W's typicaal have a viscosity measurement done at -35C while 5W's are measured at -30C.
 
Originally Posted By: Craig in Canada
. UOAs were good on M1 0W40 too, but I prefer GC for various reasons.


I KNEW there was something I liked about you! Keep those "various reasons" flying high. GC IS a magical elixer...but you already knew that! I wonder what villain
mad.gif
sold Porsche on M1!
 
Hi,
psholte - It was definitely a German. Perhaps his name was Porsche or Piech. They all come from the border country and around Zell-am-See - was the deal done over a Riesling perhaps?

The Elves were listening though as their mainstay is now owned by...................?
 
Originally Posted By: pscholte
Originally Posted By: Craig in Canada
. UOAs were good on M1 0W40 too, but I prefer GC for various reasons.


I KNEW there was something I liked about you! Keep those "various reasons" flying high. GC IS a magical elixer...but you already knew that! I wonder what villain
mad.gif
sold Porsche on M1!


I don't know you well enough to know how to take this, but I do actually have a list of reasons I prefer GC over M1 0W40 despite both giving good UOAs, they just weren't relevant to this thread.
 
Originally Posted By: ChiTDI
GC in my Toyota has never given me a problem in five Chicago winters. Car is used as a commuter with outside parking and two cold starts per day. No noise, no hard cranking.


That`s good to know,I have an older RX 300 (2001) and have used the GC over the summer,but not yet in the winter.
 
Originally Posted By: Craig in Canada
Originally Posted By: pscholte
Originally Posted By: Craig in Canada
. UOAs were good on M1 0W40 too, but I prefer GC for various reasons.


I KNEW there was something I liked about you! Keep those "various reasons" flying high. GC IS a magical elixer...but you already knew that! I wonder what villain
mad.gif
sold Porsche on M1!


I don't know you well enough to know how to take this, but I do actually have a list of reasons I prefer GC over M1 0W40 despite both giving good UOAs, they just weren't relevant to this thread.



Yes I am an enigma...a lot of members don't know how to "take" me, but then there are a few who do. I am sure your reasons for liking GC are good ones...keep using and enjoying the elixer of life, love, happiness and tribological tranquility.
10.gif
 
PS:

Great to see you back! Please don't be gone so long again. The elves in my garage (and there are still plenty, though most ironically, they're restricted to the Prius only now...) have been asking where you'd taken off to...
wink.gif


BTW, in case you hadn't heard, JK is a full bird now too -- great to see someone earn a well-deserved promo. Still not sure how I made it this far.

EDIT: Ooops, so much for being the master now ... didn't see your response in the other thread. Sorry for being duplicative. Please do, however, feel free to lapse back into the addiction (even if just from time to time).
cheers3.gif
 
Last edited:
Originally Posted By: Craig in Canada
@2KBMW:

...
GC is thin enough at 0C to earn a 0W rating - good enough for me.
As I said, GC and M1 0W40 both gave me excellent winter UOAs. I don't believe anyone has seen data from Castrol to give a full viscosity curve from -40C to 125C, but I thought that someone at one time had interpolated one from their own observations. I don't have a link.



Craig:

At the risk of inspiring the ire of my friend pscholte, AND with the caveat that I've used and loved the stuff myself, you're reading too much into the "0w" rating. Remember, the "w" portion of the SAE grading scheme is not really a viscosity, at least not directly, and not in the same way as the "hot" part of the rating. The oils that pass the "0w" testing have, as another member once put it, an ability to stay liquid and pump at freakishly cold temps, temps at which lesser lighter vis oils, would simply solidify. In short, GC is thicker than most popular 5w-30 oils, it's just very well designed, such that is stays liquid and pumpable at temps way below the "freeze" point of "lesser" oils.

But it's still great stuff, and I'd still use it all year long, even in a very cold climate. In fact, I still have a bunch of it, the green version no less, which we still use in the Prius, which is our family's only remaining 30 wt oil car.
 
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