Currently having a major issue bleeding the coolant system. I spent 2 hours on it tonight and cannot figure it out. I drive it, pull over, shut it off and crack the bleeder and a ton of air comes out but no coolant is ever needed to be added to the radiator. The heat blows hot as hell when 4k or above but when it drops to idle the heat goes cold. It's not leaking or burning coolant so I don't know what the hell the issue is. Is it possible the HG is leaking from atmosphere in allowing air into the system but not coolant to leak out?

Edit: to add the coolant issue. If I stop and just let the car idle the fans will bring the temps down from 200 into the low 190s. Ill shut the car off and crack the bleeder...no pressure. Only happens if I let the car sit idle for awhile though. If i crack it after a short drive there is a lot of pressure

 

I have done a couple and will tell you that using a spill free funnel kit to fill will really help. Some guys will put the car on an incline to help with bleeding as the rad cap is not the highest point of the system, I just used the funnel and kept it topped up just above the cap during the process. I tried to remove the air lock by opening the bleeder behind the valve cover, just made a mess when the coolant starts spitting out. To remove the air lock I had the heat on and waited until the car was up to temp, funnel will bubble and some air will escape but to push the air out I had to rev the engine to speed up the water pump and eventually the air will escape. Took some time on the first one but the second one was done in under a half hour. Good luck.

 

coolant system pressure test. don't drive car. suspected air trapped. suspected bad radiator cap.

 

I got a pressure test and found the issue. One of the hoses on the back side going to the heater core didn't have the clamp all the way on and was allowing air in, but no coolant out...not sure how that works but the issue is resolved.

Thanks guys