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 Figure 1
- Disconnect the negative battery cable.
- Properly drain the engine coolant into a suitable container.
- Disconnect the sensor electrical lead and unscrew the sensor. The coolant sensor can be found on the front, left side of the engine block, visible through, or below, the manifold, or threaded into the thermostat housing or water outlet.
- Install the sensor and tighten it to 17 ft. lbs. (23 Nm).
- Connect the sensor electrical lead.
- Connect the battery cable and fill the engine with the proper type and amount of coolant.