I fill the radiator up to where the coolant is at the bottom of the fill tube, I can't see the the tubes within the radiator a 1953 GMC. I tried the 1/16th hole in the flange of the thermostat and when the engine warms up it explodes out of the overflow tube so that's why I removed it. I don't have the gauge hooked up, I'll do that this weekend. I'm running a 50/50 mix of coolant and water.
