Don:

I do appreciate your input on antifreeze, a few clarifications. Dex-Cool is a patented GM formulation and yes is is utilized by many manufacturers. Prestone as many antifreeze manufacturers use the OAT technology to achieve long life drain intervals. I am sure most of us can recall the 50,000 mile drain intervals from the past, not the 150,000 mile as is typical today, again with the OAT technology. I suspect all new cars today specify OAT coolants independent of color.
Antifreeze color does not indicate the stabilizer technology only the color dye used, and yes Dex-Cool has a patented dye to go with the formulation.

RyeJag

 

I'll have to check but I think I recall that Dex-Cool was not actually patented by GM but is a trademarked name that GM owns and licenses to others. The actual coolants marketed under the Dex-Cool name are based on differing formulations patented by Havoline/Texaco, Zerex/Valvoline/Ashland, Prestone and others. These companies have patented slightly different formulations all based on propylene glycol but using different organic acid corrosion inhibitors or different proportions of ingredients so they can claim their mixture as proprietary and patentable.

I think the main criterion for X350 owners is that the coolant must meet the Ford WSS-M97B44-D specification and that it is inadvisable to mix coolants from different manufacturers due to the possibility of interactions between different corrosion inhibitors. So if you use something other than orange-dyed GM brand Dex-Cool, you should probably do a complete and thorough system flush to remove all traces of old coolant before using a different brand.

Cheers,

Don