I use a product called "Bolt Prep". Sold by FEL-PRO.  It is a combination
sealer, thread lube(torque accuracy) and thread locker.  Coat the threads
and flange.  Resist the urge to fill the nut.  The stuff will get trapped
and not allow the nut to seat properly.  Has worked great for me.

Dennis

-----Original Message-----
From: Joshua Van Tol <jjvantol@USWEST.NET>
To: vanagon@GERRY.VANAGON.COM <vanagon@GERRY.VANAGON.COM>
Date: Monday, May 24, 1999 1:57 PM
Subject: waterboxer head nuts leak

>Does anyone have suggestions for stopping 1.9 liter waterboxer head nuts
>from leaking? I have a presistent problem with two of them.
>
>I've tried the standard vw sealing compound, silicone, head gasket sealant,
>and even, most recently, copper sealing washers. Nothing has worked.
>
>The sealing surface on the head is a bit scarred up, which probably
>accounts for the problem. So, any suggestions? I'm thinking of trying some
>permatex 3H on the nuts.
>
>My only other recourse, as far as I can tell, is to remove the head, and
>have the sealing surfaces remachined.
>
>Joshua Van Tol -- jjvantol@uswest.net