Really Big Problem
Also check and make sure that it is the correct coolant- should be dex-cool orange not green. Also check and make sure that there is no air in the engine.
Last thing if you could update your sig so we know what you have done to your vehicle
When I blew the headgasket on my supercharged honda it was only a small leak. It was undetectable when doing a pressure test on the cooling system hot or cold. As soon as the car was up to operating temperature and I started boosting, the head gaket would start leaking from the increased cylinder pressures. My overflow tank would be overflowing and my temp gauge was pegged. After my car cooled down, everything was fine until it warmed up and I started boosting again.
Friend had that SAME EXACT problem. When it was reinstalled...they got crossed. You wouldnt think .5" would make that much diff.
try it and see.





