If you have any means to measure the temperature of your snout before you change out the oil that would be fantastic. I had a 5W-30 in there before I put in the 5W-20. i figured the thinner oil would be better since the GM stuff doesnt seem all that thick. I would make dang sure that you use a fully synthetic motor oil. That stuff turns pretty fast and I would not want to trust it to anything else.
But I think you would be okay with the 5W-30. I would just be curious as to what the temp. differences would be. Can you grab hold of your snout after a long vigorous drive in this colder weather without it burning your hand?
