What type of antifreeze do I need to use with the Webasto Thermo Top Evo system? I've come across four different types.

Thank you for your question Keith. There is no preference for the brand of antifreeze for the Webasto Thermo Top EVO vehicle or marine heater. You should ensure the antifreeze is of good quality and rated for the conditions and temperatures you will be experiencing in your location or travels. If you use a concentrate ensure it is mixed at the correct ratio.