Well,

My wife's 99 4.6L Expy has been nickel and diming me to death lately, now, the heat doesn't get warm. I just changed the Thermostat, and I only got about a gallon and a half of antifreeze out of the radiator. Also I don't think the Overflow tank is pressurzing right.. I took it off, (carefully) even after the motor was up to temp.. and I barely got a fsssst..

I put in new coolant, that I removed, I searched but couldn't find anything relevant.

I am thinking about taking it in and getting the coolant flushed..

Anyone have any ideas?