well, the guage works off the thermostat thats located by the upper radiator hose. you may have to replace it, add more coolant, or flush your old coolant and replace it. you can try watter wetter, a product that reduces the coolant temp/engine temps by like 20 degrees.

when my radiator cap was busted, to solve the high engine temps, i would turn the heat up all the way, to draw the heat from the engine away from it. i eventually fixed the problem.

03 srt-4 13.130@112.47mph (n2o, stock turbo, 10/2003)
now: 20g, portfueler, bpu+++ (track/dyno times tbd...)

i farted on your wiki