Insight Engine Coolant

I have a 2000 Honda Insight, and was recently embarking on a road trip. Noticing that my engine coolant was low I added what I had (50/50 water & Preston All Weather Protection Anti-freeze). I don’t seem to be loosing any more coolant, but my owners manual repeatedly insists that I should only use Genuine Honda Antifreeze/Coolant, and that if I use anything else it “can result in corrosion, causing the cooling system to malfunction or fail. Have the cooling system flushed and refilled with Honda antifreeze/coolant as soon as possible.” Is this really true/ necessary?



The Honda coolant is the same as your basic ethylene glycol except that is is Borate free. A tiny amount of borates from an older antifreeze won’t hurt, most new coolants are borate free.