I've heard that the low silicate antifreeze is better, but I run plain old ethylene glycol based antifreeze in mine and have never had an issue. Remember, these trucks have been in use by the military for decades, long before low silicate antifreeze was around. When I was in the army in the early 70s, it was plain old ethylene glycol based antifreeze, because that was all there was. I work for the company that previously manufactured Prestone brand. A large number of store-brand ethylene glycol based antifreeze products came right out of the same tanks that filled the Prestone jugs. I currently have Fred's brand antifreeze in both my deuces at a 50% mix. As important as the ethylene glycol content is the presence of good anti-foaming agents and anti-corrosion agents.