Originally Posted By: OVERKILL
Originally Posted By: edyvw
Originally Posted By: OVERKILL
Originally Posted By: Garak
Yep, and especially at cold cranking temperatures, there can be a reasonably significant difference, even within grades. With M1 0w-40 and GC 0w-30 both being 0w-xx, they are both decent in the winter, but one would suspect a 0w-30 to be a bit better in the biting cold. But, like I said, it's hard to compare numbers when BP won't provide them.
I never had the opportunity to try M1 0w-40 in anything yet, but I had no complaints about GC in the cold.
To add my data point, I found that M1 0w-40 (the Canadian version....) worked exceptionally well in our winters. I've used it on both the Expedition and of course the M5 this past winter and was very pleased with quiet, quick starting.
And I would certainly argue that Ontario has a lot more of what we call "winter" than California
Off course Canada is better place to determine that, but with M1 I could hear valvees below 50 degrees, while I never heard valves with GC, even starting at 9 degrees in New Mexico.
Only time when I can hear valves with GC is if I do not drive the car for 4-5 days.
I think we discussed this before. M1 0w-40 is only thinner than GC once the temperature gets REALLY cold. At 40C, M1 0w-40 is 80cSt vs 72cSt for GC. While M1 0w-40 has a higher VI, it is also a heavier oil (albeit, not by much). And so while its viscosity changes less when the temperature drops, its viscosity is higher to begin with.
On top of that, different oils have different acoustics. M1 0w-40 may simply be "louder" in your application when the lubricant hasn't warmed. That isn't necessarily indicative of any sort of problem however.
I never idicated that M1 is bad oil or something.
Still, GC has much smoother start. Also, M1 had always very rough start after not driving car for few days, not to mention that when it come sto short trips GC behaves much better.
Whatever it is, sticking to GC. Mobil could work on that a little!