Hey Alex....this is pretty great news.  For me in my 85 Tintop with a 1994 Subie 2.2 conversion, I'm noticing progressive coolant links.  Heck...there are so many connections in the whole cooling system.  Some are so minor, they do NOT drip out.  They just GAS out in vapor form.  That is my supposition anyway.
I was going to crawl under Vanagon, and just tighten whatever I could see in my vision, leak or not.  But, I see nothing at all on floor.  So....it has got to be vapor loss.  Slow.....steady.

Your advice seems a whole lot smarter.  And, it is sorta free.  And sort fun in a COVID way.  Gives me something to do.

Rich
San Diego

    On Monday, May 18, 2020, 2:31:58 PM PDT, Alex MeVay <alex@mevay.org> wrote:  
 
 Just wanted to share a tip for tracking slow coolant leaks...  Often,
the heat from running the van will evaporate small leaks without a
trace, but if you get a cooling system pressure test kit (Autozone
loan-a-tool, etc.), you can keep the system pressurized while cold
(say for a few hours), and those small leaks will stay visible.

-Alex (who sees some stainless cooling tubes and an upgrade to a
late-model radiator in his future)