probably need a new radiator cap. very cheap and easy fix.
The radiator hose which I assume you mean although you write rad, is connected to the radiator. One on the top of the radiator and one on the bottom. the one on the top
This may mean there is a weak hose OR some sort of blockage in the radiator or cooling system.
it means it is time to get a new one
If you mean "purge" the air out of the cooling system, then loosen the top radiator hose at the radiator. Pour coolant mixture into the hose until most of the air is purged and replace.
It means you have a "BIG" leak. I would check the bottom of the radiator or the lower radiator hose.
If you mean cooling system thermostat, it is at the end of the lower radiator hose at the engine side. You will have to remove the hose at the engine end to see it.
If a lower radiator hose was replaced on a 1999 Dodge Grand Caravan, but it is still leaking fluid, it could be that there is a hole in the radiator. It could also mean that there is damage to the overflow reservoir or its hoses.
It is not necessary to bleed the coolant system. If you mean "drain" the system, there is usually a plastic plug on the radiator or, you can pull the lower radiator hose off.
most lilkely blew a radiator hose or cap seal
If you mean a freeze plug, that is usually in the engine block, not in the radiator. Maybe you mean a clogged radiator. If that is the case. First you would flush it out with water. You can remove the hose from the bottom. Then reattach the hose and add water and a chemical radiator flush product that you can buy from the auto supply store. Drive for about an hour of more. Then flush out the radiator again. Refill the radiator with water and see if your engine runs cool enough. If all that does still does not work go to a radiator shop and have them rod it out. If they can't do that, you may have to put in a new radiator. Good luck. One more thing. You may also want to check the thermostat.
you mean like overheating? could be a number of problems, radiator leak, radiator broke, radiator fan, leaky hose, broken water pump, broken head or head gasket, or the car running to lean.
Assuming you mean "coolant" not water, if there isn't a drain valve on the radiator, remove the lower radiator hose and use a large/wide drain pan to collect the coolant.