If its worth anything I had them in my 96 1500 318, helped it warm up faster and as a bnous kept the engine a little cleaner. Made the most difference I think at idle, seemed to cut down on the fan blowing cold air around the engine compartment. I'm also talking about -20 - 30 C. As a side note I am pretty lazy so I left them in most of the summer 20 - 30C with no problem, although I wouldn't recommend it.


Chris