Can someone explain the warm up process (coolant movement)?

[cfiiman]

I've been looking at the crossover since I have it out and it would seem to me that coolant would flow to the radiator regardless of if the thermostat is open or not since it is before the thermo housing, is this correct?

 

[bluesrt]

usually you have a bypass hose running from the pump to the heatercore

 

[JoelW]

I've been looking at the crossover since I have it out and it would seem to me that coolant would flow to the radiator regardless of if the thermostat is open or not since it is before the thermo housing, is this correct?

bluesrt is correct. Most cars have a way to supply water to the heater before the thermostat opens so you get heat without the entire cooling system warming up first - otherwise you'd be mighty cold for a while in the winter. Normally coolant flows upward from the lower hose to the top once the thermostat opens. Some cars have a somewhat different routing depending on the type of radiator and the location of the thermostat. Taking the thermostat out defeats this and may prevent the coolant reaching proper temperature operating level.

 

[cfiiman]

Ok, then it makes sense to me looking at the crossover off my Gen 1, I somehow thought I read the thermo opening is what supplied the heater core which couldn't be right looking at where the heater hose connects, so now it all makes sense, thanks.