To keep your Mercedes Benz in working condition, you must maintain the engine's fan belt whenever necessary. This means taking quick action if it ever loses tension, malfunctions or snaps. This belt cools the engine by driving the fan that draws air in through the radiator, so it's an important component. The fan belt is held into place by a series of connection points mounting it to the engine block, and pulleys that draw the belt through a specific pattern to make its rotations.
Pop the bonnet of the car, making sure the engine is off and cool.
Locate the engine under the bonnet and observe the fan belt attached to the side of it. Carefully study the route in which the belt is attached to the engine. You will have to follow this same route when attaching the new belt.
Start loosening the bolts that tighten the belt to the engine. Begin near the front of the engine and follow the sequential path, loosening each one at a time. You'll notice the belt getting more slack as you loosen the bolts. Loosen the bolts without removing them.
Pull away the belt from the engine section by section until it is removed.
Stretch the old and new belt out all the way with both arms, measuring them to make sure that they're the same size.
Begin attaching the new belt to the engine in the same order that you loosened the bolts and removed the old belt. Pull it over the connecting points while pressing a free hand down on the slack, pulling it tightly while looping it over the next connection point so that you create tension in the belt. Repeat this process until the belt is draped over each connecting point and completely attached to the engine.
Tighten bolts one by one until the belt is fastened completely.