How to Replace Coolant Temperature Sensor 99-02 Volvo V70

Difficulty: Intermediate · About 60 min · Volvo V70

Replace the engine coolant temperature sensor on a 1999–2002 Volvo V70 and refill coolant after reinstalling the thermostat cover.

Steps

1. Drain coolant from the cold engine

   Wait until the engine is completely cold, remove the coolant reservoir cap slowly, and place a drain pan below the radiator. Open the drain and collect the coolant, then close it when flow stops.

2. Remove the thermostat cover

   Remove the engine cover fasteners and lift the cover away. Disconnect the coolant hose from the thermostat housing and remove the housing screws and cover to expose the thermostat and temperature sensor.

3. Replace the temperature sensor

   Unplug the sensor harness and remove the sensor with the correct wrench. Install the new sensor with its washer, start it by hand to avoid cross-threading, tighten to the vehicle specification, and reconnect the harness.

4. Reinstall the thermostat cover

   Check the thermostat gasket and install the thermostat with its bleed feature at the specified high point. Refit the cover and engine trim, tightening fasteners evenly to the vehicle specification.

5. Refill and bleed the cooling system

   Refill with the specified coolant and bleed air using the Volvo service procedure. Monitor temperature and leaks while operating the heater as directed, then allow the engine to cool completely and recheck the coolant level.

Check your vehicle’s repair manual for exact specifications and fit.