UPDATE
Sat I checked the new thermostat before I installed it and it didn't open until 180, so it's going back.
I drained the coolant and refilled with tap water then drained it again. I pulled the old thermostat and set it aside and reconnect the thermostat housing and connect a piece of pvc pipe to the top radiator hose instead of radiator. I plugged the radiator inlet with a rag and started water running from a garden hose thru the radiator and out the top hose. Once this was clear and clean water I tried a test. I had the radiator overflowing with water and stated the truck, the water pump would pull down the level in the radiator faster than my garden hose could fill it so I'm sure it's not the pump. I left the thermostat out and reconnected the top radiator hose and added a bottle of Prestone Radiator Flush and Cleaner Additive. Then I drove around for about 25-30 minutes. It struggled to reach 180 until I parked it.
While it was cooling down so I could drain it again I tested the old thermostat and it started opening at 160 and was fully open at 180. I drained the flush and cleaner out, re-installed the old thermostat and filled with distilled water and anti-freeze. I then ran the truck with out the radiator cap until the thermostat opened, watching the coolant level the whole time.
I did notice a few tiny bubbles in the coolant so it may be the head gasket. I had checked all of the plugs earlier and they all were all normal, not clean. So I'm thinking there may be a small leak from the exhaust into the coolant and with that and the fan belt being loose after I changed it that may have lead to the overheating.
On my drive in this morning the gauge never got about 180 which is normal. I'll see what it does this afternoon on the way home when it's in the 90's. I am going to get my hands on a
Engine Block leak test kit and test for CO in the coolant. Then I'll know if I need to change the head gasket for sure.
Thanks everyone for their suggestions.
