2003 Montana has no heat.
I changed the thermostat and it is worst than it was, it use to be warm now it's cold and the motor is running hot, Water pump???
Most likely an air pocket, or the thermostat is in backwards. Some of these can be a real bear getting the air out. I've had good luck elevating the nose up about 2 feet before adding coolant, but occasionally there is that stubborn one that I have to hook up a power flusher too to get it all out. HTH
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