There are two things you need to check when looking at the drive belts, glazed belts and cracks and both of them are responsible for poor performance. For a good belt, one should expect to see some fabric in it, unlike the glased one that will have a smooth surface due to slippage. Their beginning is always at the edge towards the inner side and then they spread outwards. It is important to replace any worn or failed belts in a timely manner, preferably all drive belts together as a preventive action. In addition, the serpentine belts, which rotate engine accessories such as alternator, air pump, power steering pump, air conditioning compressor and water pump do not show their aging signs like those with rubber casings which are characteristic of older-style belts thus necessitating regular visual checks. Thereafter change after two-three years. The new engines have single wider serpentine belt design known as Poly-V pattern that represents six narrow V-belts combined together and an engine-mounted belt automatic tensioner mechanism that provides 120 lbs (534 N) of belt tension. The used up straps may make noise or cause accessories not work properly on account of slipping off. No adjustment is necessary because there is a spring-loaded tensioner that eliminates slack on the drive belt allowing it to rotate so that it can be taken off the motor by turning the auto-tensioner assembly counterclockwise. Generally, it is fine to have cracks on serpentine belts on their rib side, but be cautious if you identify rib misses or chunks; the loss of two or more adjacent ribs; or any noises vibrational annoyances. Take 4.5L, 4.6L and 4.9L engines for instance-removing this type of accessory starts with applying downward force into square hole in tensioner using 1 inch flex handle while rotating counter-clockwise thus giving enough room for sliding it out from the pulleys. Lastly, to reinstall you will have to use the schematic and put the drive belt over all pulleys except for the power steering one, rotate the tensioner, and place it on the steering wheel's while ensuring that it touches correctly in all V-shaped grooves.
