Coolant system-cap pressure testers are readily available. You will need an
adapter for the VW cap. Yes quality is all over the place and I have even
seen some bad ones from the dealer.

Dennis

-----Original Message-----
From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of
Tom Carchrae
Sent: Monday, April 29, 2013 12:52 PM
To: vanagon@GERRY.VANAGON.COM
Subject: Re: coolant overflow fears and thoughts

Roger: Yeah, I want to build a tester gizmo.  I also have a PSI gauge that I
was thinking of plumbing into the cooling system - I have not gotten around
to it though!....  how did you build yours?  I was thinking the best design
would be an old expansion tank and a bike pump.

Larry:  I've only done the cursor blowing through the cap.  I know it holds
pressure (loosened it while warm!), and I know it can let fluid/air in/out.

Yes, pressure caps are cheap, but the rest of your cooling system +
radiators, etc are not.  I think a cap tester is a good preventative
investment. The quality of caps seems all over the place.

On Mon, Apr 29, 2013 at 9:32 AM, Roger Barkley
<rvbarkley4347@gmail.com>wrote:

>
> New pressure caps can be bad. I was suspect of my old one so ordered a
> new one from GoWesty and installed. Thought I would test the old one
> so I built a gizmo to test. It tested fine, just for kicks I tested
> the new one.....it didn't start to bleed off untill nearly 30 #'s  !
> Returned it and put the old one back on. Also went through two "new"
> front heater valves that leaked after only a month or two. Went to VW
> for the third one, two years and its still good. Moral.....be suspect of
new parts...
>
> Roger B.
>
> From:    Tom Carchrae <tom@CARCHRAE.NET>
> Subject: Re: coolant overflow fears and thoughts
>
> @Bill - I've blown through that pipe, it is not blocked.  In fact, I
> used it to drain the extra coolant out of the bottle.  I wonder about
> it being air tight though, although I've seen no leaks.
>
> @Dennis - Thanks.  I've been tempted to build a cap tester just to
> confirm my theory on that cap holding too much pressure.  I ended up
> replacing bleeder valve assembly, radiator, and at least one hose
> after that had happened.  The only other thing I can think of that may
> have caused the pressure problems was a badly routed front heater
> bypass job (the heater hose may have been pinched behind spare tire).
>
> I have done the combustion gas sniffer test, and it came out ok.  I
> guess I should have a compression and/or leak down test done again and
> see if that shows any signs.  As you alluded, I suspect it may only be
> failing when driving/under load.
>
> Any other ideas to confirm the issue before tearing the engine apart
> or replacing... :/
>