The serpentine belt on your C4 has started to make noise, so you apply belt dressing and the noise goes away - but then comes back louder than ever. Well, partner, it’s time to change the belt.
Noisy serpentine belts can be caused by wear or a loose or broken belt tensioner. A broken belt tensioner can even cause the belt to be thrown off. Thankfully, replacing the belt or

You’ll need either a ½-inch breaker bar or a belt tensioner bar to remove the belt. If the tensioner is also going to be removed, you will need a 15mm wrench.