Hi, I've been dealing with an overheating behavior in my YJ 1989 Wrangler (4.2L with all emissions control hooked up except pulse air system, Carter BBD, Auto Trans). Long time ago I've replaced cooling fluid, It was 100% tap water that is the worst choice due to corrosion; so I decided to replace it by an ethylene glycol mix as you can find them ready to pour into your cooling system. I don't know if the coolant was poor quality but immediately after replacing the fluid I was getting the engine overheated. Perhaps it was air trapped in the system as the guy replacing the coolant did all the p