The control the Mercedes-Benz Thermostats over the flow of the coolant out of the engine is how the optimum temperature is maintained in the engine.
The thermostat on your Mercedes-Benz engine is located on the top of the engine block where the upper radiator hose is connected. This thermostat is constructed with a bimetal spring that activates at a specific temperature so the heat in the engine can be properly regulated. This makes it possible for the engine to warm up and contain the coolant until a pre-specified temperature is achieved before the thermostat valve opens and allows for the hot coolant to leave. This is how the Mercedes-Benz engine warms up faster and is ready to function as it was designed too for the convenience of the driver.
If the Mercedes-Benz driver noticed the time required by the engine to warm up is longer than it has in the past then the thermostat is probably stuck open. To test this assumption the heater in the passenger compartment can be activated. If the level of heat being generated is insufficient to the needs of the driver, it is a very good indication that the coolant is not reaching its optimum operating temperature and the Mercedes-Benz thermostat is stuck in the open position. The only solution for this dilemma is the replacement of the thermostat.
The replacement procedure is very straight forward. The housing unit that this temperature control device is covered by on the engine has to be removed and its surface cleaned. Before the new thermostat is placed in the engine, it should be manually opened and closed. This way the owner will know it is not stuck closed and will close once it is installed in the engine's coolant system.