Type 4 Engine Alternator Adjustment Hole Cover

This alternator adjustment hole cover, also known as the alternator access cap, is fitted to all Volkswagen Type 4–based engines and is most commonly found on Baywindow Buses. It clips into the engine tinware and covers the access hole used for adjusting alternator and V-belt tension.

The adjustment hole is required to allow a tool to access the alternator adjustment mechanism, but when left uncovered it creates an opening in the engine tinware. This opening can allow hot air, dirt, dust, and debris to enter the engine bay, disrupting the carefully managed airflow that the Type 4 cooling system relies on.

This cap seals that opening, helping to maintain correct cooling air circulation and protecting the alternator area from contamination. A missing cover can contribute to reduced cooling efficiency and increased engine bay dirt buildup over time.

Manufactured in black and supplied as a VW Classic–style replacement, this cap matches the original appearance and fits directly into the factory tinware without modification. It is ideal for restorations, engine rebuilds, or simply replacing a missing or damaged original cap.

Although small, this part plays an important role in preserving correct engine cooling and maintaining a tidy, factory-correct engine bay on all Type 4–powered vehicles.

Other parts that may be required or worth checking when fitting:

• Alternator adjustment hardware

• V-belt

• Engine tinware seals

• Cooling fan housing components

Applications

VW Baywindow / Transporter T2 (Type 4 engines):

• 1700cc petrol: 08/1971 – 12/1973

• 1800cc petrol: 11/1973 – 07/1975

• 2000cc petrol: 08/1975 – 07/1979

VW Type 4 (411 / 412):

• 1700cc petrol: 07/1968 – 08/1973

• 1800cc petrol: 07/1973 – 03/1975