I have a 27 year old side by side GE refrigerator.

Recently it stopped working. The fan still works, but the refrigerator
part is not cool at all, and the freezer is only as cold as a
refrigerator. But if I unplug it, and leave it off for a few days, then
it starts working again for a few days. There was a light green liquid
on the floor under the fridge, but it might have come from something
that spilled.
I know the best thing would be to replace the fridge, but my mom LOVES
this fridge (why I dont know), and she wants to keep it.

Thank you.