What is the Coldest you've used GC?

Messages
71
Location
Southern ILLINOIS
What is the coldest you've started your car (unassisted for atleast 8 hours of outside temps) with GC? How did the oil and the car do? I'm having second thoughts about running GC this winter just because how thick the stuff gets below zero degrees F! I'm wondering if I would be better off using a high quality 5w-20 for start ups this winter for temps. around 0 degree F. The winters are not really bad around here, maybe a couple weeks in the single digits to a few below 0 F.
 

vad

Messages
1,856
Location
So Cal
quote:
Originally posted by HALSTEADTW: I'm having second thoughts about running GC this winter just because how thick the stuff gets below zero degrees F!
How thick? [Confused] It is a 0w-30 oil! How much thinner do you need it to be?
 

vad

Messages
1,856
Location
So Cal
Please excuse my ignorance, are you saying that in the -15F to 0F range a 5w-30 oil will be thinner than a 0w-30 one? [Confused]
 
Messages
704
Location
Bismarck, ND
quote:
Originally posted by vad: Please excuse my ignorance, are you saying that in the -15F to 0F range a 5w-30 oil will be thinner than a 0w-30 one? [Confused]
With GC 0w30, that is a true statement. If you look at one of those viscosity charts that have been posted you will see that the GC is thicker until you get really cold, say -20F and colder. At that point, the 5W oils will start to thicken, while the GC doesn't as much, thus when really really cold the GC gets a 0w rating and is thinner than the 5w30. But at those temps around 0 to -15F the 5w30 will be thinner. With M1 0w30, the charts show that it is thinner at all the cold temps as compared to 5w30.
 

vad

Messages
1,856
Location
So Cal
quote:
Originally posted by oilyriser: Put GC and 5w20 in a freezer for a few days and compare.
That's not what I'm looking for. BTW, have you done that "test" yourself or just repeat someone elses assertion?
 
Messages
2,635
Location
Chicago
quote:
Originally posted by vad:
quote:
Originally posted by oilyriser: Put GC and 5w20 in a freezer for a few days and compare.
That's not what I'm looking for. BTW, have you done that "test" yourself or just repeat someone elses assertion?

I changed the oil in 2 cars at about 10F. One car got GC the other got Citgo 5w30. The Citgo 5w30 was much "thinner" the the GC. And I mean much thinner!
 

vad

Messages
1,856
Location
So Cal
Did you keep the bottles outside for a prolonged period of time? I appreciate your observation... But I still have problems with these statements because they fly in the face of logic. A dino oil rated to be thicker while cold in reality shows to be much thinner than a praised low-temp rated full synthetic. I want to get to the bottom of this, preferably armed with some data. Can anyone point me to or post some info showing that GC is much thicker than a 5w30 oil in the -15F to 0F degree range.
 
Messages
704
Location
Bismarck, ND
This is from a previous post, just compare the M1 5w30 with the GC 0w30. I think these temps are in degrees C. Most of my cold starts are around 0 to -10F in the winter, so from that chart, I would conclude that M1 5w30 would be thinner than the GC at that temp,
quote:
Originally posted by kevm14: How about M1 0W-40? According to a viscosity chart that someone posted a while ago:
code:
TEMP * M1 0W-40 * GC 0W-30 * M1 0W-30 * M1 5W-30 * M1 10W-30 * M1 0W-20 * RL 5W-20
-20  * 2661.5   * 2609.0   * 1994.8   * 2225.1   * 3424.8    * 1712.7   * 2995.8
-10  * 1197.8   * 1127.1   * 872.4    * 944.7    * 1332.9    * 730.8    * 1165.3
0    * 599.3    * 546.6    * 428.3    * 452.9    * 595.7     * 352.8    * 521.4
10   * 327.6    * 291.8    * 231.3    * 240.1    * 298.3     * 188.5    * 261.8
20   * 192.9    * 168.8    * 135.3    * 138.3    * 164.1     * 109.5    * 144.5
30   * 121.0    * 104.4    * 84.6     * 85.5     * 97.6      * 68.3     * 86.3
40   * 80.0     * 68.4     * 56.0     * 56.0     * 62.0      * 45.1     * 55.0
50   * 55.4     * 47.0     * 38.8     * 38.5     * 41.6      * 31.3     * 37.0
60   * 39.8     * 33.7     * 28.1     * 27.7     * 29.2      * 22.6     * 26.1
70   * 29.7     * 25.0     * 21.0     * 20.6     * 21.4      * 17.0     * 19.2
80   * 22.7     * 19.1     * 16.2     * 15.8     * 16.1      * 13.1     * 14.5
90   * 17.8     * 15.0     * 12.8     * 12.4     * 12.5      * 10.4     * 11.3
100  * 14.3     * 12.0     * 10.3     * 10.0     * 10.0      * 8.4      * 9.1
110  * 11.7     * 9.8      * 8.5      * 8.2      * 8.1       * 6.9      * 7.4
120  * 9.8      * 8.2      * 7.1      * 6.9      * 6.7       * 5.8      * 6.1
130  * 8.2      * 6.9      * 6.0      * 5.8      * 5.7       * 5.0      * 5.2
140  * 7.0      * 5.9      * 5.2      * 5.0      * 4.9       * 4.3      * 4.4
150  * 6.1      * 5.1      * 4.5      * 4.3      * 4.2       * 3.7      * 3.9 
  

0W-40 is as thin as GC 0W-30 in cold temps, then becomes thicker than GC as temps go up. I'm probably going to give this oil a try in both of my small blocks as soon as I am done with my auto-rx treatments. And in the summer, I was thinking of 5W-40 T&SUV.

 
Messages
2,635
Location
Chicago
quote:
Originally posted by vad: Did you keep the bottles outside for a prolonged period of time? I appreciate your observation... But I still have problems with these statements because they fly in the face of logic. A dino oil rated to be thicker while cold in reality shows to be much thinner than a praised low-temp rated full synthetic. I want to get to the bottom of this, preferably armed with some data. Can anyone point me to or post some info showing that GC is much thicker than a 5w30 oil in the -15F to 0F degree range.
Both of the oils had been kept in the garage for weeks before the change.
 

vad

Messages
1,856
Location
So Cal
Thanks for the chart. I would really like to know the source. How come it stops at the -20 mark? According to the chart Mobil 1 5w-30 is clearly thinner in the -20F to 0F range than the 0w-X oils. Then my question would be what's the purpose of the oil weight gradation if it has nothing to do with the real world?
 
Messages
3,593
Location
Outside smalltown, IL
I used GC in the Illinois winter in my 4Runner. We had a few days where it was below zero and it was no problem. I don't drive away immediatly after a cold start in that kind of weather and with a few minute warmup I can't say I noticed any difference between it and other oils I've used. I'd run it and not worry about it. Just think about the people using 5W or 10W dinos in the same conditions and getting along fine.
 

vad

Messages
1,856
Location
So Cal
quote:
Originally posted by HALSTEADTW: Vad, what is your definition of logic?
It is not possible to give a clear delineation. If you think otherwise, be my guest.
 
Messages
2,233
Location
Wisconsin
quote:
I would really like to know the source.
427Z06 put the data together using a viscosity calculator.
quote:
How come it stops at the -20 mark?
At these cold temps, the viscosity increases by 2X for every -5 degree increment for dino oils, 1.7X for synthetics. The cSt numbers get huge very quickly & you also need to convert to cP to match the xW cold temp rating. So -20C is a very practical cut-off point for the chart.
quote:
Then my question would be what's the purpose of the oil weight gradation if it has nothing to do with the real world?
GC qualifies as a 0W-30 multigrade, per the SAE J300 viscosity chart, at 2 temperature extremes. It is a 0W since it is less than 6200 cP at -35C and it meets the SAE 30 100C requirements at 100C. No specifications exist as to what the temperature/viscosity curve does between these two temperatures. The GC 0w-30 vs. M1 5W-30 viscosity anomaly exists due to the fact that GC is 12 [email protected] and M1 5W-30 is 10.5 cSt. Since both have high VI indexes(which is really the slope or rate of change of the temperature/viscosity curve), both are getting thicker at similar rates as the temperatures get colder. It simply takes GC awhile to catch up to the M1 5W-30 & pass it up and be thinner on the way to the -35C final temp! Sorry for the long post, but that's the short answers to your questions. [Smile]
 
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