This engine heater raises the coolant temperature in the block to aid cold-starting and reduce warm-up time. It is installed in a freeze-plug or heater port on the engine block, where the heating element is submerged directly in the coolant. A failed heater produces no heat output, causing hard starting or extended white-smoke periods in cold weather. The heating element is sized to match the original assembly's wattage, so the thermostat opens at the intended coolant temperature without overloading the circuit. On reinstallation, ensure the sealing O-ring is clean and the element is fully seated to prevent coolant leakage.