97modifiedmustangGT

So I finally got all the parts in to put my car back together. Radiator had a leak and the bearing for the idler pulley on my water pump went out. During that time I changed the thermostat to a 180*. So I start it up, check for leaks and then take it for a drive. Everything is fine then the temps start to climb on my autometer electric temp gauge. It goes past 210 so I turn on my fan that pulls 4500cfm, and it still doesn't go down! Meanwhile the stock gauge barely registers (sitting on the N still). could my autometer gauge be way off? I mean it is 25 degrees here today for the high. lol

I tapped a new hole in the crossover for the sensor autometer provides. I don't know why but when the cooling system goes under pressure that sensor leaks a very small amount. were talking a drip or two for say every half hour of driving. Could that small amount of air escaping screw with the sensors reading?