The serpentine belt in the Mazda 6 is a single, continuous belt that drives the crankshaft of the engine along with the alternator, water pump, air conditioner and the power steering pump. If the belt begins to stretch thin, fray or crack, it can slip and cause components to fail, resulting in the engine overheating or your power steering pump failing to operate, for example. Replacement of the serpentine belt on a regular basis helps keep your car running properly and saves you money in the long run.
Park your Mazda 6 in a safe, flat location, such as a garage or driveway. Set the parking brake and turn the engine off. Lift the bonnet of the Mazda and disconnect the battery leads and set them to the side while you work. Locate the serpentine belt routing diagram on the underside of the hood or on top of the radiator shroud cover and refer to the chart for the exact location of the automatic belt tensioner that you need to release in order to remove the serpentine belt.
Locate the automatic belt tensioner on the front of the engine and place an appropriately sized socket over the end of the bolt that protrudes from the pulley (bolt size will vary with the year of the Mazda). Attach the breaker bar ratchet and apply clockwise leverage to release the pulley and loosen the tension on the serpentine belt. Slide the flathead screwdriver under the belt and remove it from the tensioner pulley and slowly allow the pulley to return to its original position. Remove the belt from the remaining pulleys by hand.
Place the new belt over the crankshaft pulley and route it through the other pulleys in the engine of the Mazda 6. Follow the configuration diagram for the proper routing method. Ensure that the grooves in the serpentine belt align with the notches on the pulleys, and use a small piece of masking tape to hold the belt in place over each pulley. Work your way up through the engine parts until you reach the tensioner, which should be the last pulley you route.
Apply clockwise pressure to the breaker bar and the tensioner pulley to unlock it from its automatic position. Leverage the belt over the tensioner pulley with the flathead screwdriver. Remove the masking tape strips from the pulleys, connect the battery leads to the battery, and start the vehicle. Allow the Mazda to run for several minutes while the tensioner automatically adjusts the serpentine belt.
The exact number of pulleys and components within the vehicle depends on the year and model of Mazda 6 you are driving. If you are missing the configuration diagram or your owner's manual, you can download the required paperwork at Mazda's website based upon the year/model of Mazda 6 you own. Regardless of how many pulleys are within the overall serpentine belt system, the removal/installation of the belt remains the same across all models of Mazda 6 vehicles.