Thanks to all that replied.  I am leaning toward the CV joint for the clunk
noise cause as I have been hearing some tapping noise back there.   I've had
air-cooled VWs and I'm familiar with CV joint noise but was too lazy/busy to
do anything about this (we took the trip because contractors were in doing a
portion of the Five-Year-Mostly-DIY-Home-Remodel-Project-Now-In-Year-Seven).
  The Vanagon has not been a priority.

I'll also check out the cooling system (one garage was checking for leaks
and admits they probably damaged the radiator in a pressure check), AT fluid
leak, and replace my fuel lines.  Thanks for the various tips.  The Bentley
manual is one resource but the advice of other owners/mechanics is very
valuable and can't be duplicated.

Mark

----- Original Message -----
From: Mark hersh
Date: Thursday, August 24, 2006 1:07 am
Subject: 86 2.1 L clunking noise under load
To: vanagon@GERRY.VANAGON.COM

 > Hi Everyone,
 >
 > We're new to the list and recently acquired an 86 Weekender
 > Westy (2.1 L
 > stock engine, auto trans) that we took last week from our home
 > in Seattle to
 > the Missoula MT area. Heading up a steep grade in a National
 > Forest the
 > engine made a deep clunk noise that I thought might have been a
 > main bearing
 > going south. We stopped, let it cool, checked oil and coolant,
 > and got out
 > of there. We took it easy, 50-55 mph but it made the same noise
 > going up
 > Lookout Pass (MT to ID on I-90) and I eased up on the gas and we
 > crested at
 > 15-20 mph on the shoulder. Ran fine downhill, through Spokane,
 > stopped for
 > the night having travelled about 150 miles after the first clunks.
 >
 > The next day we kept it at 50-55 most of the way and crested
 > Snoqualmie Pass
 > around 40 mph with no apparent problems and made it home ~250
 > miles. I did
 > add ATF (about a cup) and one quart engine oil after Lookout
 > Pass but before
 > Snoqualmie.
 >
 > I have been having some coolant problems and have been needing
 > to top off
 > the filler tank occasionally. In one rest stop, it did overflow
 > a bit, but
 > the gauge never ran higher than 5/8 (OK, maybe 11/16, but not
 > 3/4) and after
 > the clunk I ran the heaters if it got past 1/2. It always ran
 > less than 1/2
 > on extended downhills and 1/2.
 >
 > A friend (with no VW experience) says it's unlikely I could have
 > made it
 > back 400 miles with a main bearing going south and suggested a
 > loose motor
 > mount might make such a noise. The van has 240K miles on the
 > odometer and
 > has had some engine work done in the past (probably goes without
 > saying),but I sensed both engine and trans were near the end of
 > the wear cycles when
 > we bought him. With this trip, we have put about 2500 miles on
 > him, but
 > this was the longest and most strenuous trip we've been on.
 >
 > Any ideas? Thanks.
 >
 > Mark & Jennifer
 > 86 Weekender Wolfsburg Edition, "Monty"
 >