Engine | Preheat

Prevents oil congealing, reduces internal engine wear from cold-start oil starvation, and ensures easier starting.

"PREHEAT ENGINE" refers to the process of warming an engine's internal components and fluids (oil and/or coolant) before starting it in cold weather, usually at or below 20°F (-7°C), to reduce wear and ensure a successful start.

Are you asking about a or an external heater (like a block heater)?