NAPA sells and adapter for the vw for about 20.00 if I recall. Mighty Might also makes
  a universal tester that is a rubber expansion plug that hooks up to the universal on the
  pressure tester. I may have a couple of these still new in the box I bought last year in
  a autopart buyout. Zoltan pmail me if you want one.

  Bill

Ken Wilford <kenwilfy@COMCAST.NET> wrote:
  Zoltan, I have a Sears coolant system pressure tester that I bought
several years ago as an open box for around $35. Even though it came
with several different adapters for all kinds of bottles and radiators I
had to make an adapter for it to work on a Vanagon. The tester is
basically a hand air pump with a gauge hooked up to a hose that you then
attach to the adapter to pressurize the system. You can make your own
that would be just as good with a bike pump from Walmart. Use the
adapter that comes with it that is like a funnel and hook this up to a
piece of 7mm hose. Push the hose onto the nipple of the pressure cap on
the expansion tank. Voila! Instant coolant system pressure tester that
can also be used as a bike pump, pump up your kids footballs, etc. That
is what I would do if I had to buy another one in the future.

Just my opinion,
Ken Wilford
John 3:16
www.vanagain.com

PS I mentioned doing this in a recent newsletter I sent out. Several
guys on that list already have made their own testers. Maybe you should
join the list and get in on some of this inside info :-)
You can check it out here:
http://www.vanagain.com/newsletter.htm

Zoltan Kuthy wrote:
> Hi guys,
> I would like to buy a pressure tester with an attachment to testing the cap. Anyone knows the best one and could direct me to it?
> Zoltan
>
>
>