How To Replace the Thermostat in a 2000 Audi A8

1. Place a clean drain pan under the radiator's drain plug. Open the plug with a pair of pliers and drain approximately two gallons of coolant into the pan.
2. Locate the water outlet housing bolted to the intake manifold on the Audi A8. To do so, follow the upper radiator hose to the engine. The hose connects to the housing.
3. Loosen the radiator hose clamp that secures the hose to the housing, using a pair of pliers. Pull the hose off the housing.
4. Remove the two bolts that secure the water outlet housing to the intake manifold of the Audi A8, using a socket and ratchet. Lift the cover off the engine
5. Scrape the gasket material off the bottom of the water outlet housing, using a metal scraper or wire brush. Do the same with the surface where the housing connects to the intake manifold. Wipe debris off the housing and the intake with a clean rag.
6. Pull the thermostat out of the intake manifold. Place the new thermostat into the manifold. Make note of the thermostat's orientation inside the manifold. The end with the spring goes into the intake manifold.
7. Place the new gasket on the intake manifold. Place the water outlet housing on top of the gasket. Secure the gasket and the housing to the manifold, using the bolts, the socket and the ratchet.
8. Slide the radiator hose back onto the water outlet housing. Tighten the band clamp with the pliers.
9. Open the radiator cap on the radiator. Place a funnel into the hole and pour the two gallons of coolant back into the engine. Tighten the cap and close the hood.