2003 chevy trailblazer_ls
When you get the t-stat and housing out, grab the housing in both hands. Push down hard on a flat surface and twist the housing about 1/6 turn and release the pressure on the stat spring. You now have the four pieces, bottom keeper, spring, t-stat, and housing. Assemble in the reverse order.The service manual procedure for flushing says to remove the thermostat, drain and fill, then run the engine for 20 minutes, drain, repeat until nearly colorless, install the stat, and fill. Now, call me stupid, but if anyone can figure out how to remove the stat, then not only fill, but run the engine for 20 minutes...I'd love to hear it!!