KatsHeaters 11405 400 Watt 36mm Frost Plug Engine Heater

The Kat's 11405 is a 400-watt frost plug heater designed to keep your engine warm in cold weather conditions. This direct-immersion heater installs in place of a 36mm frost plug (also called a freeze plug or expansion plug) and heats the engine coolant from within the block.

Key Features:

• 400-watt heating element provides efficient engine warming
• Fits 36mm (1-7/16 inch) frost plug openings
• Direct coolant heating for faster warm-up than external heaters
• Reduces engine wear during cold starts by maintaining oil viscosity
• Improves fuel economy and reduces cold-start emissions
• Enables easier starting in freezing temperatures
• Standard 120-volt AC operation with grounded plug

Frost plug heaters are one of the most effective types of engine block heaters because they heat the coolant directly. This design transfers heat more efficiently than magnetic or dipstick-style heaters. The warmed coolant circulates naturally through the engine block, ensuring even heat distribution. Installation requires draining coolant and removing the existing frost plug, making this heater ideal for new installations or when replacing a corroded freeze plug.

Compatible with most domestic and import vehicles, trucks, RVs, and equipment with 36mm frost plug openings. Verify frost plug size before ordering, as engines may have multiple sizes.