The hydraulic lifters an Vanagon engines tend to "stick" until the engine is
warm and more hydraulic pressure is built up.  Mine did it at the showroom
when I first test-drove it.  It still does it if the van sits more that 48
hours in cold weather.  Never was a problem even to, some 12 years and
300,000 miles later.

-
Tim
1990 Vanagon GL
Barnegat, NJ, where we drive on the Parkway and park on the driveway.