Diesel Cruiser Winterized by Xtreme Heaters In Yorktown, VA, we have freezing weather only for a few weeks each year. My diesels have coolant that wont freeze, but the raw water should be either drained from the strainers and engines, or the engine compartment must be heated for safety. The Xtreme heater keeps the compartment well above freezing, according to my recording thermometer. The heater is not permanently installed, as it is not needed for most of the year. Once, when it was new, I happened to open the hatch, and it was just shutting off — so I knew that it worked and stopped worrying. It is one of the few heaters that the marina will allow us to use unattended. Ralph S They work great – Thanks for the good product Many Custom Installs of the Xtreme Heater