GC Cold Temp Comparison

Messages
204
Location
Cordova, TN
Comparing GC to Amsoil 5w-30 ASL and M1 5w-30, which has the better cold weather flow capabilites(perhaps rank them)? I realize that GC is 0w-30 but I have a difficult time understanding an oil's cold temp specs as they are done at different temps and I believe there is a wide range that qualifies an oil for a specific winter rating (i.e., M1 5w-30 might qualify as a 0w?). Also, there seems to be some differing info on what GC's pour point really is. Understanding high temp/viscosity is much easier.
 

Patman

Staff member
Messages
21,990
Location
Oakville, Ontario
M1 5w30 definitely doesn't qualify as a 0w30, that's why they make a 0w30 also, and it's a different formula, not just a relabeled version of the same oil. Amsoil 5w30 is a very good cold weather oil, but it too doesn't qualify to be a 0w30, which is why Amsoil also sells a 0w30, which is also a different formula. Any 0w30 oil is going to beat out a 5w oil in the cold cranking test, otherwise it wouldn't be a 0w oil. But in reality it could be overkill as many of the 5w30s out there like M1 and Amsoil already flow extremely well in winter. But if you live where it's going to get brutally cold, you'll want 0w30 M1, Amsoil or GC in there for sure, just for that extra margin of safety. A 0w oil will show you lower oil pressure on a cold start too, and your oil filter will be less likely to go into bypass, or if it does, it will be a shorter time than with 5w oils.
 
Messages
5,785
Location
Dixie
Nick, Get serious - both oils will pump at temps down to -40F, so unless you move to Alaska, it's a moot point. BTW, the new specs for the Amsoil 10w-30 show a CCS viscosity of 3100 Cp @ -25C, so it qualifies as a 5wt-30 in terms of cold cranking. Ted
 
Messages
4,844
Location
Saskatchewan
The pour point number doesn't really provide any useful info. I think they just pull those numbers out of the air. If you can find the borderline pumping temperature it's more useful because it's based on viscosity. The 0W will usually flow better at -30C and up (until they both reach the temps where their 30 rating comes into play). It has to meet a viscosity range at that temperature, while 5W only has to meet it at -25C. Anything lower, and it is possible that certain 5W's could flow better. But with 0W it's definitely going to pump down to -40C (5W is only required to pump at -30C). This is important in my climate. A 5W could meet one of the 0W qualifications - either low temperature pumpability or viscosity at -30 - without meeting the other, but if it met both it would be a 0W. Even if you don't get quite that cold, using 0W-30 or a 5W-30 that meets a 0W viscosity at -30C in the winter will improve fuel economy when driving with the engine not fully warmed up. [ October 25, 2003, 01:34 PM: Message edited by: rpn453 ]
 

nick778

Thread starter
Messages
204
Location
Cordova, TN
rpn---Thanks. This is what I was looking for. As mentioned, I am not very clear on how to decifer the winter rating spec relative to an oil's thickness or if there is spec overlap in an oil's winter rating. TS-I am serious otherwise I wouldn't be asking the question. I realize any of them will 'do' the job in most of all the lower 48. However, I was trying to gain some knowledge on understanding the cold weather specs of these oils. I've seen hundreds of posts on low/high 30 weight (ie, M1 only being 10 cst at 100 degrees and discussing how another 1 cst would make it 'better') or how a high 20 weight or low 40 weight might be better for a certain application. You're comment would also be relevant to these posts. Any of them would do. Right? We all look for the best for our application. Why? I think we're nuts. Quite honestly, I become curious when I noticed that M1 10w-30 poured from the bottle at normal temps 'thinner' or appeared thinner than the Amsoil 5w-30 or the GC 0w-30. Again, I'll admit I do not understand how to deciper cold weather specs or why they compare them at different temps.
 

cvl

Messages
150
Location
Indiana
Don't feel bad Nick, what TooSlick doesn't understand is that while the oils will all pump at -40 degrees, they will not all pump at the same rate.
 
Messages
140
Location
New York City, NY
When I was at a friend's house while doing work on my car (changing springs), I took M1 SS 5w30 and M1 SS 10w30, put them in 2 unused oil jug caps, and put them in the freezer at the bottom. After a few minutes they both had the same feel to them, but after about 30 minutes I checked on them again, and they LOOKED the same. I took a toothpick and moved it around in each cap of oil, and the 10w30 felt harder to move the toothpick in. Keep in mind, this is a freezer in a normal refrigerator, so I'm guesing it does -20 the most. So, they may have the same pour point because they won't solidify as easy, but the different pumping and cranking viscosity shows that one is easier to turn through an engine at -20!
 
Messages
7,077
Location
Ontario, Canada
I did a couple of near full throttle take offs last winter, with no warmup time, after the car had been sitting half the night at -29C (-20F) and -26 degrees C. The car survived unharmed, thanks to the M1 0w-30 I had installed in the fall. What happens to an oil pump if it's forced to pump -40 degree 10w30 at 5 gpm? edited: Maybe it would quickly heat up from the viscous friction, and there would be no problem. hmmm... [ October 25, 2003, 05:45 PM: Message edited by: oilyriser ]
 
Messages
36,290
Location
ME
you some kind of volunteer fireman? If I joined up with those guys, I'd get a remote starter for sure... [Smile]
quote:
I did a couple of near full throttle take offs last winter, with no warmup time, after the car had been sitting half the night at -29C (-20F) and -26 degrees C. The car survived unharmed, thanks to the M1 0w-30 I had installed in the fall.
 
Messages
4,844
Location
Saskatchewan
quote:
Originally posted by oilyriser: I did a couple of near full throttle take offs last winter, with no warmup time, after the car had been sitting half the night at -29C (-20F) and -26 degrees C. The car survived unharmed, thanks to the M1 0w-30 I had installed in the fall.
The oil will flow but I'd avoid that as much as possible. You want the engine to warm up as uniformly as possible since temperature gradients are hard on everything. For an extreme example, start up a really cold snowmobile and immediately rev it real hard for a while. The pistons can expand to the diameter of the cylinder before the block has a chance to warm up and expand with the pistons. Not good! [Eek!]
 
Top