When temperatures dip below freezing, there are many good reasons to preheat the engine. The different metals inside expand with heat at different rates, so quickly cranking up the engine when the pieces and parts are cold can cause damage. Additionally, cold oil doesn’t lubricate the parts as well. Starting the engine at temperatures below freezing is also hard on the battery and starter.
Most engine manufacturers require the engine to be preheated at temperatures below 20 degrees Fahrenheit. But you would be well advised to preheat any time temperatures drop below freezing. Tanis Aircraft Products and Reiff Preheat Systems produce terrific products that heat the entire engine from the inside out. Pricing varies from about $500 to $1,500 for preheaters for piston-engine airplanes.
It takes at least a couple of hours to preheat the engine, and even more in very cold climates. Some people leave their preheaters on at all times. A product called the SwitchBox allows you to turn the preheater, or any other electronic product, on and off remotely. The system costs $299 and allows you to control the preheater with your smartphone.
