another thing sounds silly is to make sure u have the wiring for the fan the right way round because the fan will suck rather than blow!!,

happended on mine mine ran in the red all week couldnt find what was wrong then realised the fans were sucking!, also i have 2 kenlowes and a 82 thermostat with that water wetter stuff in the coolant and my temps never go above a quarter on the gauge now!!.