That is a common area to crack, it happened to me too. Here is a permanent solution: http://www.rockymountainwesty.com/Vanagon_Aluminum_Expansion_Tank_p/025121403-al.htm 

Plastic replacements are cheap though, so get two, you'll need a spare!

Stuart

-----Original Message-----
From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of Neil N
Sent: Wednesday, April 29, 2015 8:01 PM
To: vanagon@GERRY.VANAGON.COM
Subject: Found solution? Re: 2.1 WBX Coolant Loss: Searched

I'm a lucky duck?  (I think I found the issue)

image of coolant expansion bottle: http://tinyurl.com/lanaowm Does this look like a crack?  Image:  http://tinyurl.com/mx7ujr5 Sorry for pic quality. These were taken with my phone camera.
As per Jim's magnifying glass comment, I only noticed what may be a crack when I viewed the image on my laptop.

If the leak were slow enough, maybe coolant evaporates off the bottle before hitting the ground? It looks like there's residue due to evaporation process.
Anyhow....

I hope this is the cause!

Neil.

--
Neil n

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