How do I Fix the Belts on a Mercedes 300E?

1. Open the hood and locate the serpentine belt routing diagram near the hood locking latch on top of the plastic cover that surrounds the radiator and the fan. Refer to this diagram when routing the new belt.
2. Remove the plastic cover from the top of the radiator by pulling out the locking pins that are located on both sides of the plastic cover. Then, turn the pins counter clockwise and remove the cover. Place the plastic cover on the ground.
3. Locate the automatic belt tensioner on the right hand side of the crankshaft pulley. The tensioner has a roller pulley on one end with a bolt head that attaches the roller pulley to the tensioner arm. The bolt head also has a set screw in the middle of it. Loosen the set screw by turning it counterclockwise with a flat head screwdriver. Only turn the set screw about a half of a turn to loosen.
4. Turn the tensioner counterclockwise from the bolt head with the breaker bar and a metric socket. Once that the tension is off of the belt, pull it out from under the roller pulley and release the tensioner. Then, pull the breaker bar off of the bolt head.
5. Slide the belt out of each pulley. Then, turn the fan with your hand so that one of the fan blades is positioned at the top of the engine. Then, slide the belt around the fan blade. Keep positioning the fan blades at the top of the engine and sliding the belt around each fan blade until the belt is completely around the fan. Then, pull the belt out of the engine compartment and match it to the new belt to make sure that the new belt is the proper size.
6. Route the new belt around each fan blade by also turning the fan blades to the top of the engine. Then, route the belt around each accessory pulley by referring to the belt routing diagram on top of the plastic cover. Once the belt has been properly routed, turn the tensioner counterclockwise with the breaker bar and socket again and slide the belt under the roller pulley. Release the tensioner and remove the breaker bar and socket.
7. Tighten the set screw back down tight with the flat head screwdriver.
8. Inspect the belt to ensure that it is completely inside of each pulley. Then, crank the Mercedes E300 for about 10 seconds. This will finish seating the new belt inside of each pulley. Turn the engine off.
9. Recheck the belt and put the plastic cover back over the top of the radiator. Then, close the hood.