Here's a general guide. Always consult your vehicle's repair manual for specific instructions and torque specifications, as they may vary slightly depending on the engine. (A Haynes or Chilton manual would be helpful.)
Tools You'll Need:
* Socket wrench: The size will depend on the sensor's nut; it's likely a 12mm or 13mm.
* Ratchet: To turn the socket.
* Socket extension(s): May be needed to reach the sensor.
* Wrench: Possibly a box-end wrench as a backup.
* New coolant temperature sensor: Ensure you get the correct replacement part for your specific engine. Your local auto parts store can help you find the right one using your VIN or engine information.
* Shop towels or rags: To clean up spills.
* Gloves: To protect your hands.
* Optional: Catch pan: To collect any spilled coolant.
Steps:
1. Locate the Coolant Temperature Sensor: The CTS is typically located on the engine block, near the thermostat housing or intake manifold. It's usually a single-wire or two-wire sensor. Refer to your repair manual for the exact location on your specific G20 engine (it varies slightly depending on engine type).
2. Disconnect the Electrical Connector: Carefully unplug the electrical connector from the sensor. Gently pull on the connector itself, not the wires.
3. Remove the Sensor: Use your socket and ratchet (or wrench) to unscrew the sensor from the engine block. It might be slightly stuck due to corrosion; if so, use a penetrating lubricant like PB Blaster and let it sit for a few minutes before trying again. Be careful not to damage the threads on the engine block.
4. Install the New Sensor: Screw the new CTS into the engine block by hand until it's snug. Then, carefully tighten it with your socket and ratchet to the manufacturer's specified torque. Do not overtighten.
5. Reconnect the Electrical Connector: Carefully plug the electrical connector back onto the new sensor.
6. Check for Leaks: After reconnecting, start the engine and let it run for a few minutes. Carefully check for any coolant leaks around the new sensor.
7. Check Coolant Level: Inspect the coolant level in the overflow tank and add coolant if needed.
Important Considerations:
* Coolant is hot: Remember to let the engine cool completely before starting this repair.
* Engine type: The exact location and procedure may slightly vary depending on the engine in your G20 (e.g., 4.3L Vortec V6, 5.7L V8, etc.). A repair manual is invaluable here.
* Corrosion: If the sensor is very corroded, you may need to use a penetrating oil to help loosen it.
* Torque specification: Overtightening can damage the sensor or the engine block. Always consult your repair manual for the correct torque.
* Safety First: Wear safety glasses and gloves to protect yourself from hot coolant and potential injury.
If you are uncomfortable performing this repair yourself, it's best to take your van to a qualified mechanic. They have the tools, experience, and knowledge to do the job safely and correctly.
