I have a 98 Taurus SE Duratec w/69k miles on it. Ever since I bought the car, the thermostat has not acted as I thought it would. It responds to the car warming up, reaches a little over 1/3 of the way up the dial, then stops. It never moves any higher. The fan does engage and i've never had any overheating problems, but even sitting in the car on a hot day in traffic it still stays right at that level. Any ideas? Should I replace the thermostat, or should i just not worry about it since the fans engage? If anyone knows of a guide on how to replace the thermostat, that'd be great too. Thanks.