Water… Distilled? Purified? Hose??

dusterdoug said
I am definitely not looking for cheap, just cool. I have a 440 stroker small block, long duration cam, and an Eastwood crossflow aluminum radiator along with a Derale 2100 cfm 2 speed fan. With a Flow Kooler mechanical pump, it would get to 210-215 after about 30 minutes of cruising around town (in 95 degree heat) and I would quickly head to the house! I have since changed to a Speedmaster electric water pump and will road test that soon.

This all prompted me to think about the coolant. Right now, I have hose (well) water and 1.5 bottles of Water Wetter. I just bought an additive called Engine Ice to try also - Engine Ice

The "type" of water you use won't have an effect on how cool your engine runs. It only affects how much deposits will build up in your cooling system over time.

It might be best to change the title of the thread or start a new one asking for solutions to your hot-running issue. My first guess is your fan and/or shroud setup is restrictive or not moving enough air, if it's only happening in low-speed stop-and-go driving. IIRC 2100 CFM isn't close to being enough air flow to cool an engine like that.

Next guess is your engine doesn't have enough initial/base ignition advance.