Surprise coolant leak.

I have a 1995 wagon. Just replaced the alternator. While installing the new alt, I noticed that I was leaking coolant. Did not find source. Any ideas?

Could be one of the freeze plugs on timing side of cylinder head. Where did you see the coolant

Yeah, where?

There's the overflow by the alt, the hose from the rad cap to expansion tank/overflow, rad cap, water pump, head gasket, freeze plugs, heater core.
^all those are just the passenger side of the engine.

I would take a picture of it. Better yet (carefully) look for coolant leaks when the engine is warm... It should be pressurized, and hopefully the leak will show itself.

Get a pressure tester as a free loaner too at AutoZone or Advance Auto. I found my head gasket leak that way. In your case, it probably something else