Thank you Jerry. OK, but since I'm a newbie here let me ask for clarification. If a hose to the heater has a shutoff valve, which I assume is needed or you'd have hot coolant (oxymoron) and heat in the cab always, and it's shut off/closed, does this prevent circulation through the block when cold starting? Would a "bridge" connection between the heater hoses ahead of the heater core, creating a "primary" loop for circulation that's always open, then the heater valve after that used to allow circulation in the "secondary" loop (heater core) be appropriate? Sounds like the heater valve being closed and stopping the flow could be problematic.
Rob
