How to Replace a Mercedes Thermostat


1. Locate the thermostat housing that sits near the front of the engine next to the water pump. The housing has two water hoses that run into its underside from the radiator.
2. Detach the two bolts on the thermostat housing that are holding the cap in place with a metric socket wrench. When the bolts are removed, use a flat-edge screwdriver to lift the cap off the thermostat housing.
3. Lift the thermostat out of the housing and use a piece of emery cloth to clean any remaining gasket material or debris from the thermostat housing and cap.
4. Spread a layer of gasket seal around the edge of the thermostat housing and place the new thermostat on top of the housing.
5. Place the cap back on the thermostat housing and secure the bolts with a metric socket wrench. Take the cap off of the radiator and fill the coolant back to the proper level.
6. Start the engine and check the thermostat housing to verify that there are no leaks.