My '93 6 cly GMC truck temp gauge started indicating very cold temp from startup to highway driving. I replaced the therm. and no change. Then I change what I thought was the sending unit, the one on top of the engine near the thermostat. No change. Now my temp gauge is fluxuating from cold to pegged in the hot range and check engine light is on and off. The truck temp is running normal and I know this is an indication problem. I have read other posted messages and someone mentioned a sending unit on the right side of the block. Is there one for the 6 cylinder 4.3 eng? If so, let me know and I will check that next time get to the truck.
Thanks