Your van sounds very normal, for all the reasons stated by many
responses.
DO NOT assume that this is a sign of bad heads leaking exhaust into the
coolant.  For six years the experts kept telling me this but the
evidence didn't add up.  In my case, in an '85 1.9l WBX, my own gut feel
was that the heating problems I was having were due to the cooling
system just not being able to handle the cooling load under heavy
driving loads.  That implied a bad radiator.  I kept putting off
replacing the radiator, partly because all the 'experts' (BTW, not on
this list) kept telling me "It's the heads, these things are famous for
that".  Through my own stupidity and bull headedness I finally drove one
time to many while overheating and blew a freeze plug (and cracked the
block).  When the new engine was in and the van started, low and behold,
it still overheated:  bad radiator!!!  Moral of the story:  Not every
overheating problem is caused by a leaking head gasket.  BTW, when the
old engine was examined it had never been out or worked on before and
was running great at 182,000 miles.  Might still be going if I'd changed
the radiator and not listened to the 'experts'.