ben:

good chance problem is (i) air in system or (ii) failed closed thermostat.

(i) many good posts on air bleeding technique. critical detail: holding
engine @ about 2000 rpm. may have to bleed at both front and rear
(expansion tank).

(ii) loosen clamp on cold exit hose FROM radiator and see if coolant pumps
out - if so, flow through radiator and likely failed closed thermostat.
probably best to loosen clamp at thermostat housing.

40 psi can damage system. be gentle.

dan

On Wed, 26 Sep 2007 08:53:46 -0600, Ben Cichowski <cichowski@MONTANA.EDU>
wrote:

>Hi All,
>
>I'm pretty new to owning a Vanagon - bought an '88 Wolfburg Weekender in
>Iowa and drove it back home 1300 miles to Montana with very few, if any
>problems.
>
>Now, it is overheating. It did this only for very brief moments on the
>interstate drive back home, but now it does it all the time. I've searched
>through archives and tried nearly everything (I'd be glad to write this up
>to share with other newbies, but want to get to the question at hand).
>Thought it was the fan/thermo switch at first....but....
>
>The hose feeding coolant to the radiator is hot, and the one exiting is
>cold. I'm thinking both should be fairly hot (within 20-30 degrees of each
>other at least) So, I'm down to two possibilities (I think...)
>
>1. Plugged radiator - I completely pressure flushed out the radiator and
>filled with the proper mix of fluid (this did not work). The passenger
side
>of the radiator gets warm, but the driver's side does not. It stays cold
>enough that the fan does not turn on (I've check or replaced every
>possibility associated with the fan as a few things needed to be done
>anyway- switch, resistor, fan motor, fuses, etc).
>
>2. Weak water pump - according to the guy who sold it to me, he put in a
new
>water pump 5K ago, so I am guessing it is not this??
>
>Do any veterans have advice?
>Is there a RIGHT way to trouble shoot this?
>
>I think I am still looking at a plugged radiator. I got water to flush
>through it under garden-hose pressure, but a lot of grey water came out
and
>I know 40 psi is a lot more than what the water pump puts out. I am living
>on Montana wages with a new baby on the way so I am hesitant to take a
>chance on buying a new radiator for 200 if it is just a guess. Please
Help!