Hey guys... I have a faulty water temp gauge in my '86 pickup. It reads cold when cold, and slowly comes up to normal operating temperature as it should, but it will not reflect overheating. I have installed an electric fan and pulled the thermostat probe after the truck warmed up (to induce overheating), with a multimeter temp probe in the top radiator hose and clamped it off. Both sending units (the one on the thermostat housing AND the one closer to the firewall, on the intake manifold I believe) have been replaced with new Toyota units. Also have been thru three or four gauge clusters to try out new gauges. I figure normal operating temp is around 195 degrees, too hot is anything above 245-250. I let the truck get to 239 degrees, and the temp still showed low side of dead even on the gauge; this is obviously not reflecting accurately. Is there ANYTHING left I can try or do to correct this issue, or will I just have to suck it up and get a gawdy aftermarket water temp gauge? Any help would be greatly appreciated.