[DaveWharran]

Jim,
I had trouble early on with radiator core to tank failures. I'm running a variable speed electric pump.
Turns out that the electric water pump controller program was great for fast engine warm ups, but would shock the radiator with 180/190 degree water all at once causing the core (thin aluminum) to crack from the tank (thicker aluminum). There is no thermostat in my setup.
The cure was to keep the electric pump moving at a minimum speed all the time, including warm up. This results in a little longer engine warm up but circulates the ever warming water through the radiator.
ERA recommends a hole in the thermostat which should do the same thing as the minimum speed thing I did with my pump.
If you feel the water pipe coming from the engine just before the radiator, it should warm up gradually, not all at once.

Dave