Because diesel engines require much higher temperatures to fire the fuel, they’ve always been harder to start in cold weather than gasoline-powered vehicles. To warm things up before the engine can run, a variety of heaters have been developed that keep various parts of the vehicle warm and snuggly even when it isn’t being driven. Some of these gadgets may be on the vehicle when you buy it; others you can buy and install later on if the need for them arises.Block heaters: Many diesels come equipped with built-in electric-powered block heaters to keep the engine block warm overnight. You just park the vehicle, plug the heater cord into a heavy-duty three-pronged extension cord, and then plug the extension cord into a 110-volt electrical socket that can handle a three-pronged plug. When shopping, don’t skimp on the length of the extension cord — it can be 50 feet to a socket from a motel parking lot! In Alaska, where a block heater is vital, electrical outlets are built right into some parking meters.