Drivebelts on the engine's front side are important in running the car and other parts. Their nature of work and material used in making them make them to wear out with time leading to need for routine check-ups and adjustments to prevent major engine damage. The number of belts depends on what accessories are installed: some drivebelts operate alternators, air conditioners and power steering pumps as well. You can visually inspect the belts by opening the hood while the engine is off since they are positioned right at its very front. Feel it using your fingers to see if there are any cracks, splitting apart, fraying or glazing. In addition, all ribs should be equal in depth from one another when viewed from below. Belt deflection can be checked by applying pressure half-way between pulleys for each belt. There are two adjusting assemblies mounted on the front of the engine that can perform this task if required: a tension adjustment assembly or a pivot assembly; each belt will have one adjusting assembly with a slider bolt and a lock bolt. The slider bolt is turned to adjust drivebelt tension after loosening the lock bolt. Do not attempt moving this assembly using a prybar during belt adjustment process. When replacing the belt, remove it by slipping off the pulleys; ideally, all belts should be changed at once. In order that you fit in properly replacement belts must be marked together with corresponding pulley grooves having similar details about dimensions; take along old ones when going for new ones so as to compare directly lengthwise , widthwise , design-wise . Lastly tighten all belts carefully .