Park your car and ensure that it is in Park (automatic transmission) or Neutral (manual transmission). Turn off the engine and apply the parking brake to ensure the vehicle is immobile during the repair.
Locate the serpentine belt. The serpentine belt is a long, narrow belt that wraps around various pulleys on the front of the engine. It is usually made of rubber and is responsible for driving the alternator, water pump, power steering pump, and air conditioning compressor.
Locate the belt tensioner. The belt tensioner is a spring-loaded device that helps maintain the proper tension on the serpentine belt. It is usually located near the top or bottom of the engine, and it will have a pulley on it.
Release the tension on the serpentine belt. To do this, use a wrench to loosen the bolt on the belt tensioner. This will release the tension on the belt and allow you to remove it.
Remove the old serpentine belt. Once the tension has been released, you can use your hands or a pry tool to remove the old belt from the pulleys.
Install the new serpentine belt. To do this, place the new belt around the pulleys in the same way that the old one was installed. Make sure the belt is properly seated on all the pulleys.
Tension the serpentine belt. Once the new belt is installed, use the wrench to tighten the belt tensioner. This will apply tension to the belt and ensure it is properly seated on the pulleys.
Check your work. Start your car and let it run for a few minutes. Listen for any unusual noises or vibrations. If everything seems to be in order, you have successfully replaced the serpentine belt.
It's important to note that these are general steps, and the exact process may differ slightly depending on the year and model of your Mercedes 300 E. Always consult your vehicle's owner's manual or seek assistance from a qualified mechanic if you are unsure about any part of this repair.
