I have a 86 300zx (1/86) with 248,000 miles. The temp gauge goes past half all the time but only by a little amount. I installed a illumanted gauge cover and broke the water temp needle. The water pump was replaced 40,000 miles ago, thermostat about 300 miles ago, original radiator, coolant flushed yesterday, coolant cap replaced, and other stuff. Is the gauge innaccurate or is the radiator finally tapped out ? I want to go to MSA in april with no problems cruising down 5.