I have a 92 chev s10, 2.8 v6, that appears to have a leak right under the passenger side motor mount

SOURCE: 92 Chevy Astro-leaking freeze plug behind motor mount

there are a couple of ways to fix the problem. first you can use pepper to plug the hole if it is a small leak. If it isn't, then use radiator stop leak. You can find this at a parts store

SOURCE: leaking water from front passenger side, under dashboard

It is either condensation water from the A/C unit that should go out a drain tube to the outside (only if A/C or Defrost is on) or a leaky heater core. If it is a heater core you can usually smell a coolant smell and the water will be warm and your windows will fog up inside. Heater core is more common. Joe ASE Master Tech

SOURCE: 2001 Chvy van: overheat+water leak/from strange(new?) hole

seems u have a blown head gasket or cracked head!

SOURCE: Leaking Freeze Plugs

usually what will make them leak all at the same time is when coolant becomes weak and freezes in cold weather ,coolant expands and puts pressure against the plugs.

SOURCE: Air Conditioning water leak inside

The drainage tube for the evaporator case is plugged causing the the condensation to drain inside instead of outside the car. The car will probably need to be lifted to find the drainage tube. Use a pick to gently remove the debris blocking the tube. You must be very careful as not to puncture the evaporator core.