VWTypeIFanBelt

The fan belt at the rear (nearest to the rear of the vehicle) of the engine plays an important role in the operation of the engine and its components. Due to its function and material make-up, it is prone to failure after a period of time and should be inspected and adjusted periodically to prevent major engine damage.

The Volkswagen drive belt needs more regular inspections than a water-cooled engine drive belt usually needs because if it slips or breaks the consequences are more serious, more quickly.

The drive belt is used to turn the generator or alternator. On Type 1 the belt is used to turn the cooling fan also. On models equipped with air conditioning or an emission control air pump, additional belts are installed to drive the accessory components.

With the engine off, open the deck lid and locate the belt at the rear of the engine. Using your fingers, move along the belt checking for cracks and separation. Also check for glazing, which gives the belt a shiny appearance. Both sides of the belt should be inspected.

Tension of the drive belt is checked by deflecting the belt with your thumb midway between the pulleys. The belt should only deflect 1/2" or so. If the belt is too loose it will slip, causing the generator or alternator not to deliver its full output and also causing the cooling fan not to cool the engine properly. If the belt is too tight, the bearings in the generator or alternator will be over-stressed.

Adjustment of these belts takes a little more time than usual. There is no tension pulley. The pulley on the generator is split into two pieces and the gap between the two halves governs the effective diameter. The gap is regulated by spacer rings. If the belt is too loos, the gap between the two halves must be decreased by removing one or more spacer rings. Spare spacers are attached to the outside of the pulley.

To remove the belt and split the pulley, lock the pulley by inserting a screwdriver between the edge of the inner flange and the top generator bolt. Remove the nut and clamp ring from the center of the outer pulley half. The outer half of the pulley can now be separated from the inner half. To tighten the belt, remove one spacer and then reassemble everything (place the removed spacer on the outside of the pulley). Check the tension again. Be careful when installing the outer half of the pulley to get it square. It helps if the engine is rotated. This will get the belt into the running position. The engine can be easily rotated by placing a wrench over the bolt in the center of the crankshaft pulley.

If the tension of the belt is not as specified, more spacers must be removed. If there are no spacers left to remove, the belt is over-stretched and must be replaced with a new one.

From air-cooled engines Tune-up and Maintenance guide