Engine Coolant Temperature Sensor: Removal

WARNING: This page is about a different car, the 2003 GMC Sierra, 2003 GMC Cab & Chassis Sierra, 2003 Chevrolet Silverado, and 2003 Chevrolet Cab & Chassis Silverado. However, it is still accessible from the selected car via links, so may be relevant.

Turn ignition off. Disconnect negative battery cable. Drain coolant below level of Engine Coolant Temperature (ECT) sensor into a suitable container. Disconnect ECT sensor harness connector.
On 4.3L models, ECT sensor is located on left side of engine, toward rear of cylinder head. See Fig 1. On 4.8L, 5.3L and 6.0L models, ECT sensor is located on left side of engine, near front of exhaust manifold. See Fig 2.
On 8.1L models, ECT sensor is located on right side of engine, near middle of cylinder head. See Fig 3. On 8.1Lmodels, Disconnect the ECT sensor electrical connector and remove the ECT sensor electrical connector from the oil fill tube bracket. On all models, remove ECT sensor.

Fig 1: Locating Engine Coolant Temperature Sensor (4.3L)

Courtesy of GENERAL MOTORS CORP.

Fig 2: Locating Idle Air Control Valve, EVAP Canister Purge Solenoid & Manifold Absolute Pressure, Engine Coolant Temperature & Throttle Position Sensors (4.8L, 5.3L & 6.0L)

Courtesy of GENERAL MOTORS CORP.

Fig 3: Locating Engine Coolant Temperature & Manifold Absolute Pressure Sensors & Throttle Actuator Control Motor (8.1L)

Courtesy of GENERAL MOTORS CORP.