[s-cars] Coolant leak

[Bob Frizzell]

S-men,
We're in a deep freeze up here in Alberta and my car's developed a coolant leak.  I've looked for the source a bit and it seems to be from the right side of the radiator about 3 inches from the bottom.  I'm not up to pulling the rad out until the weather warms up a bit.  Do any of you have an opinion on the stuff you pour in the radiator (such as Bar's leak).  Does it do any harm to the water pump, water jackets or anything else?  Is there one that actually is effective?
Always appreciative of your opinions,
Bob
93 S4 freezing in Edmonton.