overheating temp guage
First the problem, engine temp gradually gets to hot after 10 or so miles of interstate speed but cools down immediatly at stop sign. First guess is a stopped up radiator then, a faulty thermostat (only partially opening) then, bad waterpump, then slipping belts, then engine timing. Finally after all else failed I removed the thermostat altogether. Guage read cold and did not climb but heater didn't work either. When I pressed clutch pedal just enough to touch throw out bearing I noticed the lights would get a little brighter. Duh! I had a marginal ground that would feed through the temp. sending unit. The higher the sending unit signal, the better the ground through it and the higher it would read. Installed braided ground strap from motor mount bolt to frame. PROBLEM SOLVED!!!! I now have a freshly cleaned radiator, a new thermostat, a new water pump, a new timing belt and idler, and new fan belts. I'm supposed to be a mechanic, and old one at that. I hope this helps some other poor soul. I coulda checked my grounds with some jumper cables.
88 Sam 4.16t/c lockrite rear 225-75's on stock wheels and suspension.