Joy,

You are describing what sounds to me like a compression leak (headgasket)
into your cooling system.

IIRC bearings in Vanagons are sealed and are not adjustable as your friend
mentions. If somehitng was worng with them, you'd be hearing them growling and
howling while you drive.

Brakes can stick and cause a bunring smell as well. Unfortunately, w/o
Smell-O-Vision, I can't tell what your friend is sniffing at. Sticky (front) brake
calipers can do this. Same for brake shoes (in back).

Someone pretty much has to tbe agt the van when the symptoms are present.
Take it for a dirve for a few miles with your mechanic to attempt to expose the
problem. Once things have cooled and vented, smell goes away. You can't smell
what's not there.

BenT