There is no other reason the water temp wont come up other than the thermistat.
Whether the gauge moves or not, start the car run it for 10 min, then feel the upper hose and see how warm it feels. If that is warm your gauge may not be working properly.
Whether the gauge moves or not, start the car run it for 10 min, then feel the upper hose and see how warm it feels. If that is warm your gauge may not be working properly.
