Q: How do I fill the cooling system in my 1994 C220 Mercedes

To properly fill your cooling system, you need to start with the engine cold. With the engine off, fill the radiator slowly until the level is about 1"below the neck. Leave the cap off and with the car in park and the brake set, start the engine. Turn on the heater to max and allow the car to idle and warm up. As the engine warms up, the coolant level may drop, so you add a little more until the engine is fully warmed up, there is heat blowing out of the heater, and the level is correct. Then you can re-install the cap and fill the overflow tank to the correct level. Be careful about looking into the radiator, if there is any malfunction in the engine, it may blow HOT coolant back out into your face! If you are not confident doing this, you can contact Your Mechanic. They can send a technician to your home or office to top off your cooling system right there on the spot.