Originally Posted by Rusty

If you have a oil cooler with a thermostatic plate. You will not have any problems down to 50F. The plate stays cracked open a little to keep oil flowing through the cooler to keep the oil warm. So that when the plate opens fully. The system is not getting shocked with cold oil. Moisture in the oil starts to evaporate at 110F. By the time it hits 180F. All of the moisture is gone. I would install a cooler cover at 50F. Higher if you want to feel safer.

If you don't have a thermostatic plate. You can make a plate out of sheet aluminum that you can duct tape or zip tie in place. I would do this at around 60F. Depending on how hard you are going to push it.

Remember, you are only dealing with 5 to 6 quarts of oil.