If you have a diesel truck you probably already have one. So
But gasoline trucks may be lacking or have an air to oil cooler. Which is what you don't want in the winter.
Yes most have a thermostat but everyone I have tested l allow at least some oil though.
Cars pretty much never have an oil cooler.
But the engine oil in a car can take roughly double the miles to warm up as compared to the coolant.
There was an old post on here about it but I can't seem to find it.
My big block Chevy had an oil to air cooler.
I am going to replace the air to oil cooler with an oil to water cooler. A stainless steel 40 plate 250psi rated heat exchanger.
I bought this heat exchanger to do a coolant to ATF heat exchanger but have since decided to go with a manual transmission.