SAE 30: This oil is also suitable for air-cooled Beetles, but it is thinner than 20W-50 oil and may not provide as much protection. It is best used in warmer climates.
Synthetic oil: Synthetic oil is a good option for air-cooled Beetles because it is more resistant to breakdown and can help to improve engine performance.
When to change the oil:
The oil in an air-cooled VW Beetle should be changed every 3,000 miles or 6 months, whichever comes first.
