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Makes 🢒 Chevrolet 🢒 2005 🢒 Colorado Pickup - 4WD 🢒 Bulletins 🢒 Missing Chamfer For ECT Sensor O-Ring On Cylinder Head Part Number 12611423 - keywords 06-06-01-017C after coolant cooling CTS engine leak no seal sensor oring temp temperature

Missing Chamfer For ECT Sensor O-Ring On Cylinder Head Part Number 12611423 - keywords 06-06-01-017C after coolant cooling CTS engine leak no seal sensor oring temp temperature

Subject:Missing Chamfer for ECT Sensor Oring on Cylinder Head Part Number 12611423

Models:2004-2006 Chevrolet Colorado
2004-2006 GMC Canyon
2006 Hummer H3
with 3.5L Engine (VIN 6 - RPO L52)


The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.

Condition/Concern:

Some replacement cylinder heads (part number 12611423) may not have a ountersunk / chamfered opening for the ECT sensor oring like the original cylinder head. As a result, the ECT sensor oring may not seat properly once the sensor is installed.

Recommendation/Instructions:

If this concern is experienced, perform the following suggestions and install the cylinder head:

  1. remove the ECT sensor oring
  2. apply Loctite 565 (GM Part Number 12346004 [in Canada, 10953480]) to the ECT sensor threads
  3. install the ECT sensor.

Please follow this diagnostic or repair process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed.