What are the symptoms of a stuck thermostat, I replaced my water pump and thermostat about a year and half ago, about 2weeks ago my jeep started taking longer and longer to warm up, my heater is not working to well either, before it took 5-8 min to get up to temp which was roughly 200-210, now after 30min I'm sitting on about 130-140, is this signs of a thermostat issue or something else. Thanks

 

Stuck open (like it might be the case with you): slow warming up engine, slower heat, running rich for longer as a result and decreasing mpg's as a result of that (however, not per se noticable)

Stuck closed: normal (or relatively quick) warming up engine, followed by overheating. Cool(er) upper radiator hose.

 

Go to the dealer and purchase a 52028186 stat.