Always. Then I let it just ease off towards wherever it's going until it's at least a little warm. I came to notice how tight engines get when it's cold when I bought a Cessna. Flopping that prop by hand was a whole lot harder when it was less than 40 and felt like it was nearly seized below zero and synthetic oil wouldn't help with that. I could preheat it which loosened it up considerably which was easy with a small propane stove and flexible duct. You can't do that with a road vehicle so I take it easy until things warm up a bit. Aluminum expands and contracts a lot more than cast iron which is what I assume caused all that drag in the continental that went fairly unnoticed with any iron block I ever manually flipped over. All those aluminum blocked cars today surely must have some Degree of that cold tightness as the Continental so I take it easy when they're cold.