wagoneer cooling system

I recently purchased a 1988 Wagoneer and am having some cooling system trouble. I have read some of the threads on pre 92' 4.0 L 6 Cyl. and it seems that I may be having the closed cooling system problems. I had the thermostat replaced and the serp belt changed but the strange part is that the jeep wont heat up and it still pushes coolant. Any suggestions?