If it is a pin hole try using Bars Leak. If it is larger try using JB Weld to seal it. If you use jb weld, be sure the surface is clean and dry and give it plenty of time to cure.
assuming you have no water in the radiator. there can be several causes for this. one is the radiator has a hole, the water pump bushing is bad and leaking, you have a cracked block or head, or you have a blown or rusted through freeze plug, or your heater core could be leaking as well. or a hose has a hole in it. fill it up and see if you can find any leaks. if there is water in the radiator. it can be a bad thermostat, bad water pump, cracked head or blown head gasket.
A bad radiator is a radiator that is leaking or clogged. If you are loosing coolant then you have a leak that should be easy to find if the leak is at the radiator. If it is clogged your engine will overheat.
You may have a bad radiator cap.
bad radiator cap
There are a lot of reasons why your cars is leaking coolant , some can be a bad water pump, a bad upper radiator hose or a lower or it can be a bad radiator it self , is can be bad head gasket,or your radiator is not holding Enough PSI the normal range is 8-14. so i hoped i help the best i could.
Bad radiator fan motor; bad radiator fan relay; clogged radiator; thermostat stuck closed; loose belt; bad water pump; hoses leaking;
Several possibilities: 1. Radiator is leaking. 2. Coolant hose is leaking. 3. Hose clamp is loose. 3. Seal on water pump is leaking. 4. Overflow container is leaking. 5. Radiator clamp is loose or bad. Two highest possibilities: Radiator or hose is leaking.
if it leaks on left side of engine at hose,could be a bad water pump! on 3.1 engine. if pump is bad it will leak out of releif hole on bottom of pump!
could be a cracked radiator, bad radiator cap, a busted radiator or heater hose, bad heater core, or a busted fill box!
Radiators do not have exhaust.
From easiest to hardest: Does radiator have enough coolant? Is the fan working? Could be a bad thermostat. Water pump (there is a small hole in the bottom of the water pump. If there is water dripping out of the "weep" hole, then the water pump is bad). Could be a blown head gasket. (Is there any water in the oil or does the coolant in the radiator have a fuel smell?
either your radiator is leaking,head gaskit is leaking if it's your head gaskit leaking you will have water in your oil or water coming out your exhaust pipe,or you might have a freeze plug going bad.