Okay, I swapped out the t-sat back to my old one (lucky I kept it). Temp is still a bit higher than normal but no more spiking to the red. Leak returned after I topped it off with coolant/water. Called myself bleeding it but no coolant ever came out only steam. (maybe it got too hot too fast) Fans came on and couple of minutes later went into overdrive, ran so fast I could hear them in side the car. Drove it around a bit but it didn't go into the red. I read somewhere on here what the lines are on the temp gauge so the temp was a bit to halfway between the last long line and the beginning of the red. (whatever that temp is) The 304 code came back with the 1518. Now what oh GM guru?