How do I Replace a 2002 Audi 4.2 Thermostat?

1. Remove the upper radiator hose from the thermostat housing. To find the housing, follow the hose from the radiator to where it connects to the engine. The hose connects to the housing. To remove the hose, squeeze the compression tabs on the hose clamp together with a pair of pliers and then pull the hose off the housing. Drain the fluid out of the hose, back into the radiator by holding the hose vertical.
2. Remove the bolts that secure the housing to the intake manifold. Use a 12mm socket with extension bar to reach the bolt heads. There are two bolts in total.
3. Lift the thermostat housing off the engine. The timing belt makes it a very tight fit but removing the thermostat housing without removing the timing belt is possible.
4. Lift the old thermostat gasket off the engine. Inspect the engine and the bottom of the thermostat housing. If any old gasket material exists, wipe it off. Ensure the surfaces are clean.
5. Pull the old thermostat out of the engine. Replace it with a new one. The end with the spring sits inside of the engine while the end with the pin (jiggle valve) sits inside of the thermostat housing.
6. Place a new gasket onto the engine and bolt the thermostat housing back into place.
7. Slide the radiator hose onto the thermostat housing and clamp it into place with the band clamp.