1. Gather the necessary tools and parts. You will need a new thermostat (part number 90916-03103), a 5/16-inch Allen wrench, a screwdriver, and a coolant mixture.
2. Park the car on a level surface and allow the engine to cool down.
3. Locate the thermostat housing. It is located on the front of the engine, just below the distributor.
4. Use the Allen wrench to loosen the two bolts holding the thermostat housing in place.
5. Remove the bolts and the thermostat housing. Be careful not to spill any coolant.
6. Remove the old thermostat from the housing.
7. Compare the old thermostat to the new thermostat to ensure that they are the same size and shape.
8. Install the new thermostat in the housing.
9. Replace the thermostat housing and tighten the bolts.
10. Refill the coolant reservoir with the coolant mixture.
11. Start the engine and allow it to run for a few minutes. Check for any leaks around the thermostat housing.
That is how you replace the thermostat of your 1998 Toyota Camry.
