Your fan belt should be checked regularly, and this can be done with a brief visual inspection. If the fan belt is old, it is advisable to replace it. This will give you peace of mind, and you can keep the old fan belt for identification purposes or as a spare.
DOING A VISUAL INSPECTION OF THE FAN BELT
Do a visual inspection of the fan belt. Examine the inside track of the belt as well, as this is where deterioration of a fan belt originates.
Inspect the fan belt for signs of cracking, fraying, splitting or a visible hard glazed surface.
REPLACING THE FAN BELT:
Loosen the bolts that secure the alternator. This will allow the alternator to swivel towards the cylinder block, making it easy to remove the old fan belt.
Slip the new fan belt into position over the pulleys, at the front end of the engine. Ensure that the alternator is at its minimum distance from the block. This will ensure that you do not have to force the fan belt over the pulleys, possibly damaging the fan belt in the process.
Ensure that the new fan belt does not have any twists in it. Tighten the alternator mounting bolts enough to allow you to move the alternator without difficulty.
Using a lever or screwdriver, tighten the fan belt, using the block and alternator as your pivot points. Tighten the fan belt allowing about 10mm to 12mm of movement at the centre stretch of the longest run between pulleys.
Tighten all of the securing bolts that were originally loosened.
Do not force the fan belt over the pulleys. If you use an instrument or crank the engine, you could damage the cord inside the fan belt, and cause permanent damage to the fan belt.
Greater tension is required should you be fitting a multi-ribbed fan belt. The allowable movement for these fan belts is only 6mm to 8mm between the pulleys.