My buddy Jake swore by the 5W-40 synthetic for my old 7.3 Powerstroke in the winter

I always ran 15W-40 year-round here in Michigan, thought he was just wasting cash. Last January it was -10F and my truck cranked over like it was summer. He was right, the thinner oil made a huge difference on cold starts. Anyone else switch to a lighter winter weight and see a real change?

3 comments

3 Comments

dixon.rose22d agoMost Upvoted

Can't believe you ran 15W-40 in Michigan winters.

green.mason21d ago

@dixon.rose is right, that oil's way too thick unless you're running a block heater all night.

jake_mason3021d ago

My uncle ran 15W-40 in his farm truck for 20 Iowa winters and never had a crank issue, even below zero. I get what @dixon.rose is saying, but a good battery and block heater seems to matter more than switching oil weights for just a few brutally cold days a year.