I drove a 1984 Vanagon for 146,000 miles and had the same problem. The leak was however was between the cylinders and the crankcase. The problem occurred at about 50 thousand miles. It was easily solved by using a radiator/block sealer. This was added to the coolant once and the problem never occurred again.
Later, at about 100,000 miles, I visited a VW dealer and asked about potential problems that I might experience as I continued to drive this car. I was told that I might expect to have a coolant leak between the cylinders and the crankcase. When I told the service manager my experience, she said, well, you probably won’t have any more trouble. She was correct. I didn’t.