Car Engine and Other Systems - Test drive-belt tension
Check the tension and condition of your drive belt (or, with many cars, multiple belts) every month. Belts that are too tight can wear out the bearings in accessory components, such as AC compressor, water pump, and power-steering pump. Belts that are too loose will wear out faster and may fail prematurely. Perform your examination before you start the car to avoid injury due to a hot belt or moving engine part. Check for tension by pressing in the center of the belt's longest exposed run while holding a ruler next to it. If you can depress the belt 1/ 2 to 1 inch (13 to 25 mm), but not more or less, the tension is good. If not, adjust the belt tension yourself according to your car's service manual, or have your dealer or auto repair service do it. Also check for belt damage, such as glazing (often due to oil leakage), fraying, and cracks. If you spot damage, have the belt checked by a pro and replaced if necessary.