Thank you very much M.B. Doc. You have helped me tremendously. Today I used a digital temp. sensor layed up against the cooling fins, where the hot fluid enters the radiator, and the hottest temp. I could get was 181'F. My gauge was reading just under the 100'C mark. The reading from the temp. sensor was 48 ohms at that time too!! That does not correlate correctly to the gauge or the temp. I'm getting with the digital sensor. My guess is the sensor is a little off as well as the gauge. I bought a 10 ohm resistor today and will put in tomorrow.
Thanks for your help, your the only one that has been able to help me with this.