I have installed a new original type temperature gauge in my 1952 Chevy Pickup with a 1956 235 engine with a 160 thermostat. The gauge works inconsistently. At times after driving for several miles, the gauge goes directly from 100 to 180 at other times it doesn't increase at all until I shut off the engine and then may go up to 180 or all the way to the 220 mark. The engine does not seem to be running hot even on very warm days after many miles of driving. Any thoughts or suggestions.
