The diameter of the belt pulley directly determines the speed of the water pump and thus the cooling capacity of the engine. A simple trick of the engine developers consists of the use of small pulleys, which result in a higher speed of the water pump. The increased speed results in a faster flow rate of the water and ensures a better cooling performance. This is an advantage both in standard operation and especially in trailer operation, trips in midsummer and in mountainous terrain.
The belt pulley is attached to the water pump with four screws and can be removed after the ribbed belt has been released. Once the new pulley is mounted, the original ribbed belt or a up to 20 mm shorter belt can be used. The belt tensioner has sufficient capacity and allows some clearance at the belt length. If the built-in belt has already been in operation for a few years and has extended accordingly, we recommend the installation of a new ribbed belt.
Diameter: 138 mm