Bleeding my NX was a royal PITA!! Eventually, I had to put the front end up on jack stands. Then I opened the radiator & relief valve on the thermostat to get all the air out. Turn your heater all the way open. Watch for a steady stream from the Thermostat relief opening before closing it..
As for the Water Wetter, that stuff works REALLY great... In fact, it works too good...
Do not put in more than 1/2 bottle... Otherwise you will not have much heat next winter.
I agree with Tekkie & Jen above.. You must have all 4 parts working to resolve this problem: Properly mixed Coolant with air bubbles removed, working coolant thermostat, working radiator fans with good relays & fuses, and working/non-leaking water pump w/good taunt belt... Otherwise, you overheat..
You should be able to feel water moving thru your large radiator hoses if your water pump is working;
Your fans should come on when the temp sensor (behind the oil filter) is unplugged;
The water pump should be dry and not dragging/making noise when in operation;
You should be able to feel water moving thru your lower radiator house if the thermostat has opened up...