1995 Cadillac Eldorado Owner's Manual - Page 216

You can run the engine to keep warm, but becareful. I Run your engine only as long as you must. This saves fuel. When you run the engine, makeit go alittle faster than just idle. That is, push the accelerator slightly. This uses less fuel for the heat that get and it you keeps the battery charged. You will need a well-charged battery to restart the vehicle, and possibly for signaling later onwith your headlamps. Let the heater runfor awhile. Then, shut the engine off and close the window almost all the way to preserve the heat. Start the engine again and repeat this only when you feel really uncomfortable from the cold. But do it as little as possible. 4-29