Gasoline is a thinner that will eat up seals or harden them too. I do not even put any in winter as some mix it in. In the M923 I put Kerosene with dieselfuel lube like Howes. This being said, when the engine is warm and restarted during a warmer day, the truck will make a puff of white smoke with a distinct slap at start up - similar to when using ether. I never get that with diesel at warm start up. So,I do not like to do it unless I have to when it is -10 outside. The block heater and the heat exchanger coolant pump combo I installed have kept things pretty warm-on cold days, though. The pump itself warms the coolant alone.