Seems like adding a coolant filter could be more logical than adding an additional oil filter. The number one killer of engines is a cooling related problem. It would make sense that cleaner coolant could be a big help. Another killer for engines is a leak that lets air into the cooling system. It oxygenates the coolant and leads to corrosion. To prevent this all your hoses need to be clamped correctly and tight. I am surprised that nobody sells a coolant hose sealant material that absolutely seals the hose to the nipple, but will still allow the hose to be removed later. Sort of like Loctite for hose ends.