Ford: 1991 Ford Explorer Heating, warm thanks, thermostate

Question
Hi, 1991 Ford Explorer. 4.0 liter 6 cyl. I have some heat sometimes. My guage goes up and down. I changed the coolant and the thermostate and still get no heat. The hoses to the heating core both feel warm so it seems like that is ok. I don't really know what the problem is. Just blows out cool air and sometimes just alittle warmer air but not that warm. Thanks and I hope you can be of some help!

Answer
The coolant is probally warm in the hoses, to the core, but the core itself could be plugged. Remove both heater core hoses flush the core, with a garden hose until the water runs clear. Then, add coolant, and run the vehicle. Let me know how things go... Ty