Put GC, Penz 5-30 and castrol 10-30 in the freezer.

[Rick]

Well 10 hours later and castrol 10w-30 looked and movied like honey. Probably not a good oil for the winter.
The pennzoil 5W-30 didn't look to bad. The color stayed the same and it still moved around.
The GC moved around to but the funny thing is that the penzoil was very close to the GC.
For some reason the engine does start better with GC over pennzoil. So who knows maby it has to do with more than the VIS of the oil when cold.

 

[Dr. T]

Rick you need to be a little more scientific. What was the freezer temperature? -18C?

Were the results as expected? You were after all, testing a 0, 5 and 10W oils?

Why would you say that the 10W wouldn't be a good winter oil? Because it was slightly thicker than the others? Does that really matter?

 

[Drew99GT]

I've put castrol 10w-30 in my freezer as well, and it was pretty bad. Very viscous, even compared to pennzoil 10w-30. So, that's not a bad thing

I sure as heck wouldn't use it in the winter!

 

[medic]

The BradPenn 5w-30 ( VOA) advertises a pour point of -45F. This seems a bit on the cold side for a dino oil. I wish there was some way to acuratly test this.