Roger: Yeah, I want to build a tester gizmo.  I also have a PSI guage 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 leakdown 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... :/
>