In my opinion you almost can't change the coolant too much on a 20+ year
old vanagon ..
as a-frz deterorates in it's corrosion-prevention qaulitiesover time,
you never get all the old out really ..
it's often not done ...
and corrosion is the main enemy of vanagons...
Every two years , the 'forever' standard, still applies I think.

on the bong ..the higher the better I'd think ..to get 'higher.' one end
compared to the other.

I don't find the need for one though.  I don't even find the need to 'go
nutty' on bleeding.

Just top of the pressure bottle ( and maintain license plate bottle
level )every warm up-cool down cycle for a while ...like up to 6 cycles.
Air will work its way out .   Just top up the ( when cold )  air space
on top of the pressure bottle. . Expect that there may always be some
air space there eventually .... ..but if it's like 2inches..top up with
your a-frz mixture. After a number of cycles you won't be able to get
any more in .  I find that  to be plenty bled.
Besides, it's good to check things now and then after you do any work on
the rig, fora while.

On 11/29/2012 7:49 PM, Dennis Haynes wrote:
> Why do you think you "have" to change it? Coolant can also be tested for
> condition and additive effectiveness.
> What type do you plan to use? Why?
> And there should be no need for weird fill or bleed methods. The main trick
> is to fill-bleed with engine cold.
>
> Dennis
>
>
> -----Original Message-----
> From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of
> JRodgers
> Sent: Thursday, November 29, 2012 8:37 PM
> To: vanagon@GERRY.VANAGON.COM
> Subject: Libby Bong and coolant change
>
> Have to change the coolant in both of my '88GL's. Have decided to make a
> "Libby Bong" for the task - but - I have found most of the recommended
> dimensions for the bong - the one that eludes me is  how long or tall to
> make it. I know instructions say tall enough to be over the height of the
> radiator vent - but just how tall/long/high is that? Does anyone know??
>
> Bong PVC pipe - 2in. dia by "X"in long?
>
> Other parts --
> Plumbqwik Reducer - 2 in down ti 1-1/2 in.
> Nylon tube - 1/2 dia X  "X" in. long
> Rubber band
> Sticky/pucky to seal nylon tube to te PVC pipe.
>
> Thanks,
>
> John Rodgers
>