Engine Block Heater
An electric heater installed in the engine block to warm the coolant and facilitate starting in freezing weather.
An engine block heater is an electric heating element installed directly into one of the core plug (freeze plug) holes or inline with the cooling system of an engine block. Powered by an external electrical cord plugged into a standard wall outlet, it warms the engine coolant while the vehicle is parked.
By heating the coolant, the block heater warms the engine block, oil pan, and internal components. This is highly beneficial in freezing winter climates: it thins the cold engine oil to ensure rapid lubrication upon start, reduces wear on the starter motor and battery, and allows the vehicle cabin heater to blow warm air almost immediately.
Block heaters are standard equipment on many diesel vehicles, which are difficult to start in cold weather due to reliance on compression heat for fuel ignition. Using a timer to activate the heater two to three hours before driving is the most energy-efficient way to use a block heater.