Yes, I meant NOT properly pressurized. The system could also pressurized but with air or vapor pockets. 

Dennis

-----Original Message-----
From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of Larry Alofs
Sent: Sunday, September 13, 2015 8:15 AM
To: vanagon@GERRY.VANAGON.COM
Subject: Re: Thermostats...question(s)

did you mean *not* properly pressurized?

On Sun, Sep 13, 2015 at 1:20 AM, Dennis Haynes <d23haynes57@hotmail.com>
wrote:

> Bubbling and gurgling in the cooling system is a sign that the system 
> is properly pressurized and parts of the engine are hot enough that 
> the coolant is flash vaporizing. This is a great way to cause parts to 
> warp and other nasty stuff to happen. Begin with testing the pressure 
> cap and making sure the system is fully filled-bled. If this continues 
> you need to look for the cause of either lack of pressure or if the 
> system continues getting air in it you need to find the source. This 
> is often the early signs of head gasket failure or cracked heads.
>
> Dennis
>
>
> -----Original Message-----
> From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On 
> Behalf Of Don Hanson
> Sent: Saturday, September 12, 2015 2:58 PM
> To: vanagon@GERRY.VANAGON.COM
> Subject: Thermostats...question(s)
>
>    Is there an accepted method to test the function of one of our double
> style thermostats?   I am skeptical about the proper operation of my
> currently installed one.... lately....I have had some other issues 
> with cooling and recently replaced my oil/coolant heat exchanger (mine had a pin
> hole water leak to the outside).   But I also noticed once recently that I
> could hear some bubbling in my coolant system when I shut the van off, 
> and I have not heard the fan recently.
>
>    Anyhow, I have a spare used thermostat sitting on my bench, unknown 
> condition....I'd like to see if it actually works and maybe swap that 
> in....If no worky, what kind or brand should I buy to get a good 
> dependable part?
>
>    So can I drop the spare I want to test into boiling water and measure
> it, testing for function, or some such?   It would be good to know, even if
> I do just buy a replacement, that my spare is OK and working..
>    I have calipers  to measure mechanical things.
>