How to Change the Thermostat on a Passatby Zyon Silket
The thermostat in the Volkswagen Passat regulates the temperature of the coolant as it flows into the engine. The thermostat is secured to the water pump on the lower half of the engine, and to access the thermostat inside the water inlet housing, you should drive the Volkswagen onto ramps. Allow the coolant time to cool before you work on the vehicle.
Place a drain pan under the petcock on the bottom of the radiator. Open the petcock with a pair of pliers, and drain the coolant from the radiator into the drain pan. Close the petcock.
Locate the water inlet housing by following the lower radiator hose. Remove the clamp that secures the radiator hose to the housing by using a pair of pliers. Pull the hose off the housing.
Remove the nuts that secure the water inlet housing to the water pump using a socket and ratchet.
Pull the housing off the water pump. Take note of the thermostat positioning inside the water pump. The thermostat has an arrow on it located between the two studs on the pump. When you place the new thermostat into the pump, make sure the arrow is in the same position it was on the thermostat you removed.
Pull the used thermostat out of the water pump. Place the gasket onto the new thermostat, and place the thermostat into the housing.
Place the water inlet housing onto the water pump, and secure it using the socket and ratchet.
Slide the hose onto the water inlet housing, and secure it using the clamp and pliers.
Remove the radiator cap on the top of the radiator. Place a funnel into the filler spout, and pour the coolant back into the engine. Put the cap back on the radiator.