Per another thread, you can't make it recover by shaking it.
In labs, they heat to 90C to erase the "memory" effect of cold temperature gelling.
Your engine will do it, but if you need say a 0W, your oil might not be a 0W until it's had a full heat cycle, so don't tip it in and drive at -40C.
http://www.bobistheoilguy.com/forums/ubbthreads.php/topics/3999169
Originally Posted By: Shannow
It's not "permanently" damaged per se, but coming from the cold to room temperature won't make it come back.
Here's the best paper that I've found on it, that gives a decent description (Selby papers are nearly always well worth reading 20-30 times).
http://www.instituteofmaterials.com/wp-c...n-Formation.pdf
Quote:
Explanation of Oil Memory
A reasonable explanation of oil's "memory" and the need for preheating the sample is that the structure formed in oil gelation at lower temperatures is not easily dissassociated at temperatures up to and beyond ambient.
Such disassociation to essentially individual molecules can only occur at temperatures imparting sufficient energy to those molecules to completely break up the the molecular association originally leading to structure formation.
So what I take is that if the oil is allowed to get cold enough to gel (not freeze, not sure what that does), the gel "particles" stick together, even around ambient temps, and need to be brought back up to temperature to dissolve again...otherwise it does an even worse job on the next cooling cycle.
Get it warm/hot and it should "recover".
This problem isn't limited to storage, but happens in sumps too...the longer and colder, the more gel. A few warm days doesn't allow it to recover, and some examples exist of it not pumping after some extended periods of exposure.
