Probably a freeze plug aka soft plug
Intake manifold gasket leak....big problem with that engine. Sorry for the bad news.
The radiator will need to be replaced. Sometimes, it may seem that the radiator itself is leaking but it could be the radiator "hose" that is leaking. In this case, the radiator hose needs to be replaced and clamped tightly.
Check radiator hose, leaking water pump, look for hole in radiator, leaking coolant bottle or leaking seals.
Maybe it's not the radiator. Maybe it is one of the radiator hoses that is leaking. Or possibly the radiator cap or a level sensor.
Loose hose connectors, damaged hoses, bad head or intake manifold gasket, punctured radiator or reservoir... all depends on where it's leaking at.
"transmission fluid leaking from fitting below radiator cap after replacing radiator on 99 surburban
Leaking radiator? Leaking or loose radiator hose?
It could be the radiator, the hoses, a leaking coolant tank or the water pump.
maybe your radiator is broken and you need to get a new one or just get a reparation if the radiator starts leaking when is in use it may be leaking because of the pressure of the water.
Most likely the intake manifold gasket is leaking.
Some typical radiator repair jobs are leaking hoses, leaking radiators or loose connections.
Intake manifold is leaking, or worse, cracked cylinder most likely tho, the intake manifold.