Avalanche, Sierra, Silverado, C&K Series, 1999-2005

Removal & Installation

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  1. Disconnect the negative battery cable(s).
  2.  
  3. Drain the engine coolant to below the level of the sensor
  4.  
  5. If necessary remove the engine cover.
  6.  
  7. Disconnect the electrical lead and unscrew the sensor.
  8.  

To install:

  1. Installation is the reverse of the removal procedure.
  2.  

Coolant temperature sensor tightening torques:



4.3L engine: Tighten the sensor to 17 ft. lbs. (23 Nm)
 
4.8L, 5.3L, 6.0L, 6.6L, 7.4L and 8.1L engines: 15 ft. lbs. (20 Nm)
 
5.0L and 5.7L engines: 115 inch lbs (13 Nm)
 
6.5L 18 ft. lbs, (25 Nm)
 

  1. Make sure to fill the engine with the proper type and amount of coolant.

    Click image to see an enlarged view

    Fig. Coolant temperature and oil pressure sensors-4.3L engine



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    Fig. Coolant temperature sensor-4.8L, 5.3L and 6.0L engines



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    Fig. Coolant temperature sensor-5.0L and 5.7L engines



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    Fig. Coolant temperature sensor-6.5 and 6.6L engines



    Click image to see an enlarged view

    Fig. Coolant temperature sensor-7.4L engine



    Click image to see an enlarged view

    Fig. Coolant temperature sensor-8.1L engine

  2.  

  1. Drain the cooling system to a level below the ECT sensor.
  2.  
  3. On 6.6L diesel engines, remove the alternator.
  4.  
  5. Unplug the harness connector from the ECT sensor.
  6.  
  7. Remove the ECT sensor from the engine.
  8.  
  9. 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).

    Click image to see an enlarged view

    Fig. ECT sensor mounting-4.3L engines



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    Fig. ECT sensor mounting-4.8L, 5.3L and 6.0L engines



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    Fig. ECT sensor mounting-6.6L engines

  10.  

  1. Drain the cooling system to a level below the ECT sensor.
  2.  
  3. On 6.6L diesel engines, remove the alternator.
  4.  
  5. Unplug the harness connector from the ECT sensor.
  6.  
  7. Remove the ECT sensor from the engine.
  8.  
  9. 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).

    Click image to see an enlarged view

    Fig. ECT sensor mounting-4.3L engines



    Click image to see an enlarged view

    Fig. ECT sensor mounting-4.8L, 5.3L, 6.0L and 6.2L engines



    Click image to see an enlarged view

    Fig. ECT sensor mounting-6.6L engines

  10.  

4.8L, 5.3L & 6.0L Engines




NOTE
Use care when handling the coolant sensor. Damage to the coolant sensor will affect the operation of the fuel control system.

  1. Drain the cooling system to a level below the engine cooling temperature (ECT) sensor.
  2.  
  3. Disconnect the ECT sensor electrical connector.
  4.  
  5. Remove the ECT sensor.

    Click image to see an enlarged view

    Fig. ECT sensor location-4.8L, 5.3L, 6.0L engine

  6.  

To install:


NOTE
If installing the old sensor, coat the threads with sealant GM P/N 12346004 (Canadian P/N 10953480) or equivalent.

  1. Install the ECT sensor.
  2.  
  3. Tighten the sensor to 15 ft. lbs. (20 Nm).
  4.  
  5. Connect the ECT sensor electrical connector.
  6.  
  7. Refill the cooling system and check for leaks.
  8.  

5.7L, 6.5L & 7.4L Engines




NOTE
Use care when handling the coolant sensor. Damage to the coolant sensor will affect the operation of the fuel control system.

  1. Disconnect the negative battery cable.
  2.  
  3. Relieve the cooling system pressure.
  4.  
  5. Drain the cooling system below the level of the Engine Coolant Temperature (ECT) sensor.
  6.  
  7. Disconnect the ECT sensor harness connector.
  8.  
  9. Remove the ECT sensor.

    Click image to see an enlarged view

    Fig. ECT sensor location-5.7L engine



    Click image to see an enlarged view

    Fig. ECT sensor location-6.5L engine



    Click image to see an enlarged view

    Fig. ECT sensor location-7.4L engine

  10.  

To install:

  1. Coat the threads (only) with sealer P/N 9985253 or equivalent.
  2.  
  3. Install the ECT sensor.
  4.  
  5. Tighten as follows:

    5.7L engine: 10 ft. lbs. (13 Nm).
     
    6.5L engine: 18 ft. lbs. (25 Nm).
     
    7.4L engine: 15 ft. lbs. (20 Nm).
     

  6.  
  7. Connect the ECT sensor harness connector.
  8.  
  9. Refill the cooling system and check for leaks.
  10.  
  11. Connect the negative battery cable.
  12.  

8.1L Engine




NOTE
Use care when handling the coolant sensor. Damage to the coolant sensor will affect the operation of the fuel control system.

  1. Drain the cooling system to a level below the engine coolant temperature (ECT) sensor.
  2.  
  3. Disconnect the ECT sensor electrical connector.
  4.  
  5. Remove the ECT sensor electrical connector from the oil fill tube bracket.
  6.  
  7. Remove the ECT sensor.

    Click image to see an enlarged view

    Fig. ECT sensor location-8.1L engine

  8.  

To install:


NOTE
If installing the old sensor, coat the threads with sealant GM P/N 12346004 (Canadian P/N 10953480) or equivalent.

  1. Install the ECT sensor.
  2.  
  3. Tighten the sensor to 37 ft. lbs. (50 Nm).
  4.  
  5. Install the ECT sensor electrical connector to the oil fill tube bracket.
  6.  
  7. Connect the ECT sensor electrical connector.
  8.  
  9. Refill the cooling system and check for leaks.
  10.  

 
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