- Disconnect the negative battery cable(s).
- Drain the engine coolant to below the level of the sensor
- If necessary remove the engine cover.
- Disconnect the electrical lead and unscrew the sensor.
- Installation is the reverse of the removal procedure.
Coolant temperature sensor tightening torques:
- Drain the cooling system to a level below the ECT sensor.
- On 6.6L diesel engines, remove the alternator.
- Unplug the harness connector from the ECT sensor.
- Remove the ECT sensor from the engine.
Installation is the reverse of removal. If reusing the old sensor, coat the threads with GM sealant 12346004 or equivalent. New sensors are already coated; additional sealant is not needed. Tighten the sensor to 15 ft. lbs. (20 Nm).