Volkswagen Air Cooled 1949-1969 Repair Guide

Fan Belt



On all Volkswagens except the type 3, the V-belt drives both the generator and the fan which cools the engine. On the type 3 the V-belt drives the generator only; the blower fan being mounted directly on the crankshaft of the engine, thereby rotating at the same speed as the engine. In all Volkswagen models, the fan belt should deflect approximately 3 / 5 in. (15mm) when pressed firmly at its midpoint with one's thumb. The quality and adjustment of the fan belt is especially important on the smaller Volkswagens, in which it drives the cooling fan. If the fan belt goes bad in one of the type 1 or 2 models, the car can be driven no further without causing severe damage to the engine. However, in type 3 and 4 models, it is possible to drive without the fan belt for fairly long distances, especially in the daytime. An average battery will power a car's ignition for some distance before running out of energy. However, if the headlights must also be used, the distance that can be covered will be much shorter. In short, if the fan belt fails in a VW, stop right then and there without further delay. (When you see the red light in the speedometer dial, the generator is no longer charging.) But if the belt fails in a Squareback, Fastback, or Notchback, you can drive to the nearest service area. Regardless of the model you drive, it is a good idea to carry an extra V-belt.

If belt tension is too great, the result will be a shortening of the life of the generator bearings due to unnecessary stress. If the belt is too loose, the result will be a loss of cooling efficiency in beetles and a loss of generating power in both the small and large Volkswagens. The following steps should be followed in adting the fan belt tension on all Volkswagens, regardless of year:

  1. Remove the holding nut from the generator pulley shaft. In type 3 models, the pulley must be held from turning by using a suitable wrench. In the smaller Volkswagens the pulley is held by a screwdriver wedged between the notch in the generator pulley and the upper generator housing bolt.
  3. Remove the outer half of the generator pulley and adjust the fan belt tension by fitting the proper number of spacer washers between the halves of the pulley. Each washer added or removed changes the play in the belt about 1 / 4 ".
  5. If the fan belt is too loose, one or more spacer washers will have to be removed from between the pulley halves. If the belt is too tight one or more washers will have to be added between the pulley halves.
  7. When correct adjustment has been achieved, the belt will deflect approximately 3 / 5 in. (15mm) when pressed by thumb pressure at its midpoint.
  9. When adjustment is correct, install the outer half of the generator pulley, and insert all left-over washers between the pulley nut and the outer pulley half. In this way, all spacer washers will remain on the pulley shaft and will be readily available whenever subsequent belt adjustments are required.
  11. Tighten pulley nut.

If the belt has stretched to the extent that correct adjustment can no longer be achieved by removing spacers from between the pulley halves, the belt should be replaced. Also, if a belt has frayed edges or cracks, it should be replaced. Fan belts should be kept free from grease and oil.

It is recommended that a new belt be inspected regularly during the first several hundred miles of use, since new belts have a tendency to stretch slightly.