I would like to know what people are using in their cars for coolant/antifreeze. From the factory, our cars came with the green inorganic compound fluid. That was pretty much the industry standard in the 1960's and 1970's. Since that time there have been new fluids introduced in the marketplace. The organic compound fluids, OAT, and the hybrid version or HOAT. GM has their own specification, Dex-Cool, and several of the aftermarket companies sell a "universal" coolant. These are all various colors from yellow to pink to orange to blue, etc. They all have different characteristics, positives and negatives for the collector car. I was wondering if there was a consensus as to which is best for our older Mustangs.