Stacey:

When you're shoping for a van.
Check the compression.
Make shure all ignition is BOSCH
Look for signs of Silicone sealer, If an engine is assembled properly you
never need it.
Drive the van down the backside of a shopping center real close to a big
wall with the windows down, you'll hear a lot of things this way.
Check for play in the steering.
Ask the owner for recent repair receipts.
Take a blanket with you and lay down, look under the van for rust.
Check the sellers drive way out for big oil spots,  a good van doesn't
leave  much on your drive.
Ask if the seller has any spare parts.
Many times I've found that the seller has spent considerable money on the
van and his recent parts and repair bills will prove it. In effect they
have been throwing money at a problem that they never got fixed.
Ask around and see if a list member in your area will accompany you to
look at some vans.

I looked at about ten vans before I bought mine back in 1994. They all
looked good but had various problems mechanically. I finally bought a
nice Westfalia for $2,000.00 and spent about $1,000.00 to get it back in
shape.
Most of my expendatures were tires, battery, two new cylinder heads and I
did all of the work myself. After that point I went about 35,000 miles
before I replaced the jugs and pistons and since that time I've been
about another 50,000 miles with only rare problems.

Stan Wilder
83 Westfalia Air Cooled 256,000 Mi