1. Open the hood of your Corolla.
2. Locate the engine coolant reservoir. It is usually a white or translucent plastic tank with a black lid.
3. Follow the upper radiator hose from the reservoir to the engine. The thermostat housing is located where the hose connects to the engine.
4. The thermostat is located inside the thermostat housing. To access it, you will need to remove the housing cover.
Here is a diagram of the thermostat housing and thermostat location:
[Image of thermostat housing and thermostat location]
Note: Before removing the thermostat housing, make sure the engine is cool and the coolant has been drained.