So. I flushed my radiator and notice it didn’t seem full at all. I filled it and bled it to what I thought was sufficient. I have a possible blown head gasket that is leaking gases into the coolant. I used Bars HG-1 as a bandage since the truck has 213k miles on it. I have an issue with the coolant res getting constant bubbles in while the engine is warm and pressure has built. I replaced the rad cap with a duralast cap and still have bubbles. I then replaced it with MC cap and no bubbles but at no point with any of the caps did the coolant in the res ever transfer back over to the radiator after the engine cooled. The radiator always had a small amount of fluid to be added. well today it overheated in traffic (250*) I shut it off and added a gallon of coolant and 1/2 gal of water as well as let it sit high idle (1600rpm) for a half hour. It continuously burped. It never overheated with the duralast cap that let it bubble constantly. So I’ve added coolant, burped it and put the duralast cap back on. What the actual F is going on. Typical idle temp is 185.