1995 Nissan 240 SX mileage: 102,000. I noticed my water temperature gauge was getting too high so I figured I should put anti-freeze in the radiator and that plastic jug next to it to cool it down some. After doing that, the same day (I let the car cool down while I was at work for eight hours) it still shows the gauge way up there in the red after just a few minutes of driving. The gauge isn’t broken because it does fluctuate from hot to really hot. What else could it be? Thanks in advance!