John,

Don't use any sealants when working with any O-rings.  It is not necessary.  The whole theory of O-ring is that the cross-sectional diameter of the ring is a little bit bigger than the trough in which it fits. So when the two halves of the gissmo comes together, they compresses the ring and makes the seal.  The O-ring is made of material to compress and seal.  That's why when you remove the old O-ring, the cross-section looks square -'cos it's been squished and did not return to it's original shape.  this is also the reason that you should never never reuse O-rings...even if it looks ok..once it's been compressed, it should not be reused.  

If you have problem making the o-ring stay put in the pump body while you put the other half on, you can coat the O-ring with silicon grease (very thick gooey clear stuff) and it will stay put in the groove.  Also, if you have a situation where you need to slip a gissmo with O-ring in and out of some housing (not the case of the Vanagon water pump) you can use silicon grease for lubrication.  Silicon grease can be purchased from any full service plumber stores - sometimes sold as valve lubricant.

Yau-Man Chan
87 GL

>>> "John P. Flaherty" <jflaherty@PIVOT.NET> 01/16 4:30 AM >>>
Thanks to all who're replied to my Bleeding Cooling System post. Your help is greatly appreciated. This is my first experience with an O-ring type water pump gasket. What is the preferred sealer? Indian Head Shellac? BlueGoo(RTV)? Something Else?

Thanks,

John Flaherty
'84 Vanagon
'74 Super Beetle