heater core leaking?

[xyzabcde@earthlink.net]

Hi all,

While discovering that my carbs need to be rebuilt again, I noticed that the
heater core shroud is wet around the lower heater hose but the hose looks good. 
For those of you who have already had this problem, where does the coolant first
appear when the core starts to leak?  Is this the spot?  

A corollary question is: where do I get this PBBlaster stuff?  The screws
holding the heater shroud down have never been off so I might as well start
soaking them now.

Denise Thorpe