I'll second the radiator rodding as ineffective on new rads.
I paid a hefty sum to have one rodded and the car still overheated.  A new
replacement solved the problem.

Didn't someone recently mention using something like Spic N Span or CLR or
Lime away?
Maybe these products are not as severe as drain cleaner.

-----Original Message-----
From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of
Mark Dearing
Sent: Saturday, May 15, 2010 1:09 PM
To: vanagon@GERRY.VANAGON.COM
Subject: Re: What to soak radiator in to dissolve slime

In a message dated 5/15/2010 1:05:36 P.M. Eastern Daylight Time,
marcsayer@HUGHES.NET writes:

Best  solution (sorry bad pun) for a safe and effective cleaning is to
take it to  a radiator shop and have them rod it out. They will
chemically and  mechanically clean it and can tell you if the core is
good or not.

That does not work on the  newer radiators.  All that will happen  is that
they will fall apart trying to do this  AMHIK   I have  seen subie Radiators
that came back looking like they had expoded   later  mark d