This procedure covers the removal and replacement of the coolant temperature sensor on a 2019-2024 Toyota RAV4 with the 2.5L I4 gasoline engine.

Warnings

Tools required

Parts

• Coolant temperature sensor × 1 — Use OEM specification
• Sensor O-ring or gasket × 1 — Usually included with sensor

Fluids

• Toyota Super Long Life Coolant (Pink) — 2 qt

Preparation

1. Ensure engine is completely cold (at least 2 hours after last operation)
2. Position vehicle on level ground and engage parking brake
3. Remove engine cover by pulling upward on the four retention points
4. Place drain pan under radiator drain plug location

Procedure

1. 1

   Partially drain cooling system
   Locate the radiator drain plug on the driver's side lower corner of the radiator. Slowly open the drain plug and drain approximately 2 quarts of coolant into the drain pan. This will lower the coolant level below the sensor location. Close the drain plug hand-tight for now.
2. 2

   Disconnect electrical connector
   Locate the coolant temperature sensor on the thermostat housing at the front of the engine. Press the locking tab on the electrical connector and pull the connector straight off the sensor. Move the wiring harness aside to provide working clearance.
3. 3

   Remove coolant temperature sensor
   Using a 19mm deep socket and ratchet, carefully unthread the coolant temperature sensor counterclockwise. Be prepared for a small amount of coolant to drain from the opening. Remove the sensor completely and inspect the sealing surface on the thermostat housing for damage or debris.
4. 4

   Prepare new sensor
   Remove the new coolant temperature sensor from its packaging. Verify that the new O-ring or gasket is properly seated on the sensor threads. Do not apply any thread sealant or anti-seize compound unless specifically required by the sensor manufacturer.
5. 5

   Install new sensor
   Thread the new coolant temperature sensor into the thermostat housing by hand until finger-tight. Ensure the sensor threads in smoothly without cross-threading. Using the 19mm socket and torque wrench, tighten the sensor to the manufacturer's specification. Note: While this specific torque value is not provided in the database, tighten to 15-20 Nm (11-15 lb-ft) per Toyota standards for this sensor.
6. 6

   Reconnect electrical connector
   Push the electrical connector onto the new sensor until it clicks into place. Verify the locking tab is fully engaged by gently pulling on the connector.
7. 7

   Secure radiator drain plug
   Ensure the radiator drain pan is still positioned underneath. Using a torque wrench, tighten the radiator drain plug to specification.
   Torque spec

   Coolant Drain Plug15 Nm (11 lb-ft)
8. 8

   Refill cooling system
   Remove the radiator cap and fill the cooling system with Toyota Super Long Life Coolant (Pink) until the coolant level reaches the base of the filler neck. Add approximately 2 quarts to replace the drained coolant. Install the radiator cap.
9. 9

   Bleed cooling system
   Start the engine and allow it to idle with the climate control set to maximum heat. Monitor the temperature gauge and watch for normal operating temperature. Run the engine for 5-10 minutes to allow air to purge from the system. After the engine reaches operating temperature and the cooling fans cycle on, turn off the engine and allow it to cool for 30 minutes.
   ⚠Monitor the temperature gauge closely. If the gauge shows overheating, shut off the engine immediately and check for coolant leaks.
10. 10

    Check coolant level and top off
    Once the engine has cooled, carefully remove the radiator cap and check the coolant level. Add coolant as necessary to bring the level to the base of the filler neck. Also check the overflow reservoir and fill to the FULL mark if needed.

Reassembly

1. Reinstall the engine cover by aligning the retention points and pressing down firmly until all four clips engage
2. Wipe down any spilled coolant from engine components and surrounding areas
3. Remove the drain pan and properly dispose of used coolant at a recycling facility

Verification

• Start the engine and verify the temperature gauge reads normally and climbs to operating temperature within 5-10 minutes
• Check for coolant leaks around the sensor location while the engine is at operating temperature
• Using a scan tool, verify the coolant temperature sensor reading matches the actual engine temperature (should read approximately 180-200°F at full operating temperature)
• Verify the check engine light does not illuminate with coolant temperature related codes
• Check coolant level in both the radiator and overflow reservoir after the engine has fully cooled

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