Also my truck will fun very warm if stopped at a stoplight for very long. I have a 180 in there and I've tried venting the system. Idling with the cap off for almost an hour. But nothing works. It'll run over 210 then go back down. It's like a constant change.

 

Its got air in it unless the stat is sticking..

 

What is the proper way to purge the air? I've tried burping it.

 

I usually pull the 1/4" steam line hose off the radiator while the engine is running, put it in a bottle and give the engine a rev or two.

 

I'll try that tomorrow. I'll let you know what happens.