Wabasto heaters work great. Had them on our bucket trucks and on our Kabota diesel auxiliary packs. Depending on your situation there are also auto start systems which can be programmed to start the engine and allow it to run for a preset amount of time IE: start every four hours and run for 20 minutes then shut down and repeat every four hours or whatever you set it at. A buddy of mine has one on his Duramax and uses it when we go ice fishing and sledding. Works very well. I take my generator and use it to run my block heater when needed.