I have recently been somewhat suspicious that my factory temperature gauge is starting to go bad. my el Camino has a aluminum radiator and new aluminum water pump, when the gauge in the car is showing water temp close to 190 the temperature of the thermostat housing and intake is only around 160 at the most. The gauge also will make very large and drasitc changes in temp often. my question is, if these are signs that the gauge is in-fact inaccurate or going bad with age.