I've recently been researching coolant technology and decided I wanted to try and find an affordable way to get the type of coolants the manufacturers are specifying, rather than defaulting to the 1 gallon concentrated gold-colored Prestone I've been using that claim to work for "all makes and models". I know there is quite the conversation on the topic of 2-EHA coolants, but I'm not sure how the "all-makes" Prestone gold compares to the older 2-EHA coolants. The "all-makes" gold appears to just contain ethylene glycol and diethylene glycol (and proprietary inhibitors). Is Prestone simply not publishing the chemicals for corrosion inhibitors? I think the Japanese (Asian) coolants are likely all PHOAT now, but I became confused with Prestone's POAT (not PHOAT). What did they lose in the product to make it no longer hybrid? Did they remove something that was previously inorganic, such that the HOAT became phosphated OAT now? Most of my applications are Nissan Xterra/Frontier (2000-2004). Aluminum heads, radiators, and other components, and cast iron blocks. It looked like many of the other manufacturers (Zerex, Pentosin, etc) are also likely using the exact same product base, but just changing the colors to match OEM color? Is that correct? I was confused reading a label of Pentosin Pentofrost suggesting the color was even tied to a particular year range. I don't know the OEM color of the Nissan Xterra/Frontier in 2000-2004, but I'm guessing green. I think later model Nissan (all aluminum engines) might have moved to blue. ?? I'm looking for long life coolant, and I plan to flush all the old stuff out (I rebuilt some engines and everything is new). I just need to flush out the heater cores to finish the complete flush. Also, I noticed there aren't any real concentrated versions of these newer Asian long-life coolants, other than Pentosin Pentofrost, but that stuff is so expensive you can by diluted for less than half the cost from other makers. I need some help figuring my way around all these coolants. Ugh.