RMW has them for $30: http://www.rockymountainwesty.com/Coolant_Expansion_Tank_025_121_403B_p/025121403b.htm 

If you get a couple of hose pinch pliers you can change this out with little coolant loss. I like the KD brand but you can get others for less: http://www.pelicanparts.com/catalog/ShopCart/TOOL/POR_TOOL_WTD102_pg2.htm 

About a 15 minute job with the pliers.  Just top of the new tank before you unclamp the hoses. The system will purge itself in a few trips.

Stuart

-----Original Message-----
From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of Stan Shapiro
Sent: Saturday, October 31, 2015 7:57 AM
To: vanagon@GERRY.VANAGON.COM
Subject: Re: coolent 

    
Well, it turns out my coolent cap is just fine, it's a small hairline crack right at the neck of the coolant tank.  So I only lost fluid when the tank was pressurized, no fluid loss when the engine was cool and at rest.
Not being very mechanical, are there any helpful hints when I replace the coolant expansion tank?  I never lost fluid in the expansion tank. Will I need to bleed the radiator after I install the new tank?
ThanksStan

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