The coolant temperature sensor changes resistance as the coolant temperature increases and decreases.
- Remove the temperature sender from the engine.
- Position the water temperature sending unit in such a way that the metal shaft (opposite end from the electrical connectors) is situated in a pot of water. Make sure that the electrical connector is not submerged and that only the tip of the sending unit's body is in the water.
Heat the pot of water at a medium rate. While the water is warming, continue to measure the resistance of the terminal and the metal body of the sending unit:
- As the water warms up, the resistance exhibited by the ohmmeter goes down in a steady manner: the sending unit is good.
- As the water warms up, the resistance does not change or changes in erratic jumps: the sender is bad, replace it with a new one.
- Install the good or new sending unit into the engine, then connect the negative battery cable.
REMOVAL & INSTALLATION
See Figures 1, 2, 3 and 4
- Disconnect the negative battery cable.
- Drain the cooling system until the coolant level is below the coolant sensor.
- Detach the electrical connector from the sensor.
- Remove the sensor mounted in the side of the thermostat housing.
- Install the engine coolant temperature sensor. Tighten the sensor to 20 ft. lbs. (28 Nm).
- Attach the electrical connector to the sensor.
- Connect the negative battery cable.
- Fill the cooling system, start the engine, then top off.