2. Locate the thermostat housing. It is a small, metal housing located on the front of the engine, near the top.
3. There are two bolts that hold the thermostat housing in place. Use a wrench to loosen these bolts.
4. Once the bolts are loose, you can remove the thermostat housing. Be careful, as there may be some coolant that spills out.
5. The thermostat is located inside the thermostat housing. It is a small, round, metal device with a spring in the center.
6. Use a screwdriver to pry the thermostat out of the housing.
7. Inspect the thermostat. If it is damaged or worn, it will need to be replaced.
8. Install the new thermostat in the housing. Make sure that the spring is facing the correct way.
9. Replace the thermostat housing and the bolts.
10. Tighten the bolts until they are snug.
11. Fill the coolant reservoir with coolant.
12. Close the hood of your 4runner.
