I have been dealing with a very stubborn air pocket in my coolant system. Bled the truck at least 10 times per instructions and even lifted the front end up to assist bleeding. Nothing seemed to get the air out. I recently expelled some air by doing something different. I noticed lisle makes a "coolant funnel" and I decided to make my own. I just used a plain old funnel that fits in the D1 radiator hole. The truck had been bled per the instructions in the write up section here. With the truck cold, I unscrewed the radiator fill plug. I noticed the level was a little low with air in the top. I left the coolant bottle top on tight when I did this so there would be minimal fluid shift into the coolant bottle while performing this. I then filled the funnel up with coolant almost to the top. I started the truck, put the heater on high heat low fan speed and squeezed the radiator hose lightly. I noticed several large air bubbles expelling out of the coolant in the funnel. I did this for 15 mins or so until no more air came out. I then shut the truck off and carefully siphoned the coolant from the funnel until it was level with the top of the fill plug. I then put the fill plug back in the truck and drove it around the next day. So far it seems to be running cooler after doing this ( and it has been very hot outside here at 100 deg. or so). Anybody with a stubborn air pocket may want to try this.

 

I noticed when i had to bleed my system, my upper radiator hose had to be manipulated to get all the air out, since the shape of it put it at the highest point in the cooling system(where air will collect).

 

I once had to remove the heater core hoses to get all the air out .....