Im stumped, I have a 96 Mystique 2.5liter V6 24 Valve Doch with 82K original miles on it. Heres whats goin on, A few weeks ago i was driveing and all of a sudden the temp gauge went all the way to red and started shakeing, i drove home. The radator light came on and the temp gauge went all the way to red and stayed there, even when i turned the car off and turned it on the next morning. I went and bought a thermastat, installed it, added coolant, still runs hot. When i drive it i noticed after about a half mile of driveing, after reaching operating temp the coolant comes past the max line then starts bubbleing and hissing in the run-off tank, The coolant when the engine is cold goes back to the normal "max" line, but when it gets hot it comes all the way up to the cap and it hisses and steams. Possibly a water pump? I of course dont bring my cars to dealerships so please do not just say bring it to a shop, i just want your input. Thankyou