Stopped by AZ and found 6 qts of GC which I bought for the 6 for 5 special. It was of the ...4821 lot. I was surprised to see that on the label it says words to the effect that it is ok to use to -41 degrees F. Not that I will ever be in temperatures this low but I expected it would be lower given the -81 degrees pumpability in other posts. Given this stat, does this imply that there may be less poly esters in this oil than originally thought? In any event, I couldn't pass it up when I saw the oil with all the talk here about GC. I'll probably use it this winter instead of the M1 10w-30 I ususally run.