94 blazer 4x4 4.3 motor.. have changed heater core, theromasate, water pump, still reads hot,, not other signs, any ideas? runs rough at times, was woundering if converter is plugged?

 

its prolly the temp sending unit for the gauge.

 

Is it indeed running hot? Do you have a problem with coolant spilling out of the overflow bottle? If you have verified that it is not overheating, just reading high, hten it is indeed the gauge sending unit.

One often overlooked area to check is the cleanliness of the exterior of the radiator. If the cooling fins of either the radiator or A/C condenser (if applicable) are plugged up with bugs or other debris, it will run hot.

 

a faulty radiator cap sometimes causes the thermostat to read hot, try replacing the radiator cap.