In process of the coolant flush and change (PM kinda). So far I have the pull all the plugs, flush with hose pressure, drained and filled with RO water. I have been driving with RO water only the last 200 miles and really like the looks of the temperature gauge without anti-freeze. Now I’m thinking of draining and refilling with only 1 Gal of Toyota Red. The FSM says 2 Gals (I believe). In town we are lucky to get down to 40 so I don’t need 2 for freeze protection. But I want protection of the corrosive prevention and lubrication that anti-freeze will offer. So what if I added a bottle of Redlines WaterWetter to make up the difference. I can always use the extra cooling help from WaterWetter and the additional water. Would that give enough corrosion protection and lubrication?