I had the engine rebuilt in Nov. 2009 and started it in May 2010. Engine runs good. New thermostat stuck and rad holding pressure. Replaced the thermostat with 180 degree and all seamed to be OK. Took it today for alignment and 45 minutes of travel both ways. On the return trip temp ran 180 running, at lights idling 200. Thermostat not opening. Should I replace it again or pull it? The rad. cap is 16 pounds. I got no bypass thru the cap. I am concerned that the rad. is going to be compromised. I had it pressure tested but am now seeing light wetness at the upper solder joints.