I mentioned that I borrowed the Autozone pressure tester device to check out my system, and got no conclusive results.   Hey genius, the ONE key thing that this method did not check out was the Blue pressure cap itself!!  The pressure tester device requires removing the Blue cap, installing the test kit in it's place, and looking for funky decline in pressured system via the included hand pump, and also visual spots of leakage to pinpoint corrections needed.  Duh!  I think my problem is the Blue cap.

    On Friday, July 23, 2021, 5:01:23 PM PDT, Richard Koerner <rjkinpb@sbcglobal.net> wrote:  
 
  This discussion is certainly getting my attention....  My 85 Tintop with a 2.2 Subie has "I think" a new plastic expansion tank with blue cap which was installed during the conversion process; looks brand new anyway, which may be a bad thing.  And yes, I've got some annoying loss of coolant; I've tried using the AutoZone free rental of a pressure tester and everything with nothing conclusive.  Since I plan on keeping my Vanagon until I die (or slightly sooner), investing in this heavy duty tank and cap setup might be the way to go.

    On Friday, July 23, 2021, 4:43:34 PM PDT, Eric Caron <ericcaron96@comcast.net> wrote:  
 
 This post reminds me of the time I needed a new blue cap for the expansion tank.  I purchased a couple and they didn’t work correctly.

One day a friend in a vanagon stopped in and hearing of my trouble gave me a cap. He said he had replaced it years ago and was a original one.  It was old and tired, but I took off the new one and put on the old.  It worked perfectly after that, pulling and returning fluid to the overflow tank.

So, this post is making me feel good about my aluminum expansion tank, and cap.

Eric Caron