THE ENGINE COOLANT TEMP GAUGE MAY READ ON THE COLD SIDE OF THE NORMAL RANGE, OR MAY STAY BELOW NORMAL EVEN THOUGH THE ENGINE IS AT ITS PROPER OPERATING TEMP ON SOME VEHICLES. THIS IS CAUSED BY THE COOLANT TEMP SENDING UNIT NOT BEING POSITIONED IN THE MAIN STREAM OF COOLANT FLOW. INSTALL A NEW TEMP SENDER FITTING.