Where is the ect(coolant) sensor located on a 02 cadillac deville???

I can visual see it under hood. so open hood and look

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

NOTE The engine coolant temperature sensor is located on the intake manifold water jacket or near the thermostat housing. On the 4.6L engine, the coolant temperature sensor is located on the rear cylinder head, at the cruise control servo bracket. It is necessary to drain coolant from the cooling system to a level below the sensor, prior to sensor removal.

1. Disconnect the negative battery cable.
2. Drain the coolant level below the height of the ECT and recycle the engine coolant.
3. Detach the electrical connector at the sensor.
4. Remove any obstruction to access the ECT.
   1. On the Catera, this would include removing the intake plenum and the intake bridge.
   
   
5. Using a deep well socket, remove the sensor.

To install:

1. Coat the threads of the new sensor and install it in the engine. Tighten to 15 ft. lbs.
2. Install the electrical connector.
3. Refill the system with coolant.
4. Connect the negative battery cable.

It means you should try replacing the engine coolant temperature sensor as it has probably failed (it's located on the driver's end of the engine at the middle about half way down).

If you are refering to the Engine Coolant Temperature (ECT) sensor,it is located on the right rear of the engine below the exhaust gas recirculation (EGR) valve.

HINT: If your Deville is equipped with the analog instrument cluster and the temperature gauge is working, or if you have the digital instrument cluster and the driver information center (DIC) has been diplaying messages telling you that the engine is hot, the problem with your engine cooling fans is NOT the sensor.

Click over pic for zoom...



Fig. Showing the location of MAP Sensor and other components on the front of the engine: 1. Manifold Absolute Pressure (MAP) Sensor; 2. Idle Air Control (IAC) Valve; 3. Engine Coolant Temperature (ECT) Sensor; 4. Throttle Position (TP) Sensor



Fig. Engine coolant temperature sensor (1).

you have 4.6l engine ect sensor located below the egr valve. now if you have 4.9l engine ect located on the thermostat housing.

disconnect the negative battery cable.
Pull the harness of the sensor.
Drain about 1/4 of the radiator fluid.
Place a rag under the sensor and use a wrench to remove and replace the sensor.

Why replace the radiator it's just a bad sensor. Get the Haynes repair manual on your vehicle look up the water level sensor testing and replacement steps. The sensor probably cost around $30 and I doubt if it takes more than 30 minutes to replace.

Maybe this will help . although this is from a 1997 Caddy.


Cadillac DeVille Engine Coolant Temperature (ECT) Sensor Location

The engine coolant temperature sensor is located on the driver side of the engine near the rear of the engine compartment