Thanks for you help guys. Yes i did replace the T-stat when i did the LIM. From what i was told at Firestone the LIM would not cause the CO2 to be in the antifreeze. The test they ran was to identify if CO2 was present in the anitfreeze. Do any of you have any experience with this test and know if it is a accurate way to test the system? They said that it is a blue dye that they add to the system and then watch to see if it changes color and it did.