Hey guys, My 97 GTS with 30k miles has always ran pretty steady at 190F. The car has a Roe SCT Tune but Im unsure of the fan settings. Seems like my fan is always on once the car is warmed up. The other day I went for a 30 minute drive and everything was great. I noticed while driving through my neighborhood that my engine temp was slowly creeping up past 195. I was able to get it home right before she was going to hit 250. Problem is I was panicking a bit and did not pay attention to if the fan was running. As it idled in my garage it kept creeping up so I shut it off not really realizing the fan shuts off too which is unfortunate. Not sure how much higher it crept but the coolant was boiling. While off coolant came out of the front fascia bottle, not too much. When I opened the coolant tank cap there was pressure. Reading many threads about the water pump I believed this was my issue. Went out today and let it warm up. The temp never rose above 195. What I found strange and almost disappointing was when I increased the RPMs the temp was dropping to 185-190. So it seems like my water pump is working. My upper radiator hose was warm which makes me think the thermostat was open. Do they thermostats fail open or closed? Both coolant tanks seem to be full and at good levels. The only other thing I can think of is my drivers side muffler is broken internally (rattles). Is it possible that internal baffle could have got stuck in a position to clog the exhaust flow increasing the engine temp? I was actually driving the car to just get fresh gas for winter and have my replacement muffler swapped out, so this was a bummer. When I turned the heat on as the car was overheating I only had cold air. But at idle the water pumped seemed to be working today. When I turn the AC on the fan comes on regardless of engine temp. I dont feel like I hear the high speed fan ever but maybe its all I hear? No engine codes. Appreciate any help.