I just had the pleasure of replacing my heater core and my heater control valve. I have an alluminum rad, and a 1/2 bridgeported motor to install still, but I was wondering which coolant would be better. I work at a shop so I get both coolants for cost. So price is not really a big deal to me. And there's enough extra of both floating around the shop most of it will be free either way. If anyone has any info on extended life coolant in a rotary i'd love to hear it. Thanks everyone.

 

Either is fine AFAIK - just don't MIX them (don't ask me how I found THAT out...).
Personally I use the Mercedes Benz coolant - it clear, damned expensive ($22gal), but legendary in its ability to protect engine and coolant innards over the long term*, esp aluminum components. even at that price its cheap for what it protects...

*I don't mean leave it IN forever, just that using it, changed regularly, has extended component live notably in MB cars... and since our alloy rotor housings have officially been classified "Unobtainium", seems a smart investment...

Stu Aull
80GS
Alaska

 

The only issue that I saw with the extended life coolant/antifreeze back years ago was with the Dexcool. It had a tendency to seep through gaskets on older engines.