Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Coolant Temperature Sensor/Switch (For Computer): Service and Repair
2002 Saturn SL1 L4-1.9L SOHC VIN 8SECTION Service and Repair
ENGINE COOLANT TEMPERATURE (ECT) SENSOR
REMOVAL
1. Ignition Off.
IMPORTANT: Engine coolant must be drained below the level of the ECT sensor. Refer to "Cooling System Section" for drain and fill procedures.
2. Remove air induction tubing from throttle body to air cleaner.
3. Disconnect ECT sensor harness connector.
IMPORTANT: The connector must be removed by squeezing the sides. Apply pressure to the sides gently with pliers. Do not pull on wires.
4. Remove ECT sensor using a deep-well socket.
INSTALLATION
IMPORTANT: Tap out sensor mounting hole in engine head to remove thread sealant residue. Clean any sealant residue from old sensor and apply RTV sealant to threads if old sensor is going to be reused.
1. Apply thread sealant Saturn P/N 21485277 (Loctite 242(R) Threadlocker or equivalent) to sensor threads.
2. Install ECT sensor.
Torque:
Coolant Temperature Sensor: 8 N.m (71 in-lbs)
3. Connect ECT sensor harness connector. Push in connector until a click is heard and pull back to confirm a positive engagement.
4. Install air induction tubing from throttle body to air cleaner.
5. Fill engine coolant to proper level. (Refer to Cooling System for procedure.)
6. Check for leaks.
REMOVAL
Assembly:
1. Ignition Off.
IMPORTANT: Engine coolant must be drained below the level of the ECT sensor. Refer to "Cooling System Section" for drain and fill procedures.
2. Remove air induction tubing from throttle body to air cleaner.
3. Disconnect ECT sensor harness connector.
IMPORTANT: The connector must be removed by squeezing the sides. Apply pressure to the sides gently with pliers. Do not pull on wires.
4. Remove ECT sensor using a deep-well socket.
INSTALLATION
IMPORTANT: Tap out sensor mounting hole in engine head to remove thread sealant residue. Clean any sealant residue from old sensor and apply RTV sealant to threads if old sensor is going to be reused.
Assembly:
1. Apply thread sealant Saturn P/N 21485277 (Loctite 242(R) Threadlocker or equivalent) to sensor threads.
2. Install ECT sensor.
Torque:
Coolant Temperature Sensor: 8 N.m (71 in-lbs)
3. Connect ECT sensor harness connector. Push in connector until a click is heard and pull back to confirm a positive engagement.
4. Install air induction tubing from throttle body to air cleaner.
5. Fill engine coolant to proper level. (Refer to Cooling System for procedure.)
6. Check for leaks.
RENDER: 1.0x
NO RELATED
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.