I had this same issue last year.. I searched this forum and found a lot of info.. I called the local dealer and made an appointment.. I went there and told them all the info and the service guy was clueless.. I told him your tech is going to check the truck and he's gonna find the leak.. then your gonna call me and say yes there is a leak like you stated.. then your gonna order up a new updated radiator and thermostat for the truck.. and I also told the service guy the recall code.. which I don't remember now.. and my goodness when I pick up the truck the service guy said do you work for gm... I step back and smile and other employees are looking at me and I said no...