Attention: TDR Forum Junkies 
Joseph Donnelly
TDR MEMBER
I drained the antifreeeze at the radiator while changing the water pump. I did not try to overthink the situation and just planned to put in fresh stuff since the additives don't last forever. I did use Walmart water since well water isn't so good, according to the stuff I could find on the internet. I just assumed that the Valvoline, at less than half the cost, would be as compatible as it says with any residual original HOAT in the system. I read bad things about the GM OAT antifreeze but apparently HOAT is good. HOAT type should also be the most similar to the factory fill. All of them use ethylene glycol as the main component; only the additive packages are different and have to play nice together.
