Where is your drain plug on your 1990 jeep Cherokee sport?
on the bottom of the oil pan
If you take the grill off of the front of the vehicle you should be able to see the radiator. Look on the passenger side of the radiator, your wing nut type plug should be on the side of the radiator. The Jeep Cherokee radiator drain plug is plastic and very fragile. You should remove the lower radiator hose to drain the cooling system.