Hi todd,

        I don’t think it is cracked as with the other caps it would hold pressure after a trip for 5 or more days until I would check it.  the Expansion tank would then fill when I opened the cap.  now the tank fills when cool and there is equal pressure.

Eric Caron 
85 GL Auto 

> On Jul 20, 2016, at 8:34 PM, Todd Last <rubatoguy@comcast.net> wrote:
> 
> Check your coolant resovour. I have seen them crack near the threads for the cap in a way they are not easily detected.
> 
> If the cap does not work.
> 
> Sent from XFINITY Connect Mobile App
> 
> 
> ------ Original Message ------
> 
> From: Eric Caron
> To: vanagon@GERRY.VANAGON.COM
> Sent: July 20, 2016 at 5:23 PM
> Subject: Coolant Mystery positive update
> 
> Hi folks,
> 
>        Earlier I posted about my concerns with my expansion tank showing air when running.  Also, when stopped for long or short times the pressure remained high in the tank and air was in the expansion tank.  Over flow seemed to not change.  I changed the blue cap several times.  Just before leaving and returning from West River Westies I put on a known good original VW cap gifted from a friend who had just found another new original.  
>        With the known working cap my system seems to be operating perfectly again.  the expansion tank fills back up after a long trip and the over flow tank goes down when the appropriately. 
> 
>        Can my engine heads actually be ok and the other behavior be due more to the cap?  Or, is the cap working well masking the introduction of the exhaust gasses and now I just don’t know they are there? 
> 
> It sure acts like a healthy coolant system at the moment! 
> Eric Caron 
> 85 GL Auto Westfalia.