tensioner is not a major project. Anyone who can use a breaker bar and follow a diagram can do it. Start the project by contacting Zip Products (www.zip-products.com), where you can obtain the correct belt and the tensioner. The only other items you will need are a few common hand tools and about an hour of your time.
    Our C4 had a serpentine belt that was really singing the blues. We also discovered that the belt tensioner was broken. In less than an hour, the entire project was completed and our C4 was back on the road, minus the noise.

     For access, remove the mass air flow sensor and flexible duct by unclipping the mass air flow sensor from the air inlet duct at the front, then loosening the band clamp that holds the flexible duct onto the throttle body. Remove the flexible duct and position the mass air flow sensor off to the side.