Do I fill the radiator with water or 50/50 see antifreeze.

Pam are you sure it's boiling? If the Antifreeze is boiling I'd think you'd see steam coming out of your reservoir as the water expands into the reservoir, but you didn't say you see anything like that.
Of course engines get hot, that's why we have the cooling systems but it doesn't sound like it's "boiling" to me with no signs of visible steam unless your antifreeze level is really low?

If it's really boiling, and you antifreeze level is good, then your reservoir should be getting filled up with expanded hot water that goes into it to catch it when it expands.

If the water isn't going into the reservoir, then maybe your antifreeze level in the radiator is too low and you need to add antifreeze?
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Best to fill the radiator with the engine cooled down. If you ever have to open the radiator when it's hot, NEVER open it with your bare hand as you could get scolded with boiling water. Instead use a big thick towel to remove the radiator cap off a hot engine. Again, if you can, just wait until the engine cools then open the radiator cap.

With the engine cool, you can fill the radiator with a 50/50 antifreeze mix. The 50/50 mix come premixed 50 percent water, and 50 percent antifreeze. So you can throw that stuff straight into the radiator.

Non mixed antifreeze needs to be mixed 50/50. Some people use 50 percent distilled water when they mix it because distilled water doesn't have the minerals in it that may get stuck in your radiator. That's being a bit picky about it though. Tap water works fine in a pinch. The other 50 percent is antifreeze. You can mix it right in the radiator too, put in a measured amount of the antifreeze, followed by the same measured amount of water. The water pump will mix it all together when you run the engine.

Put the cap back on and run the engine and if/when the water "boils" it should go into your reservoir. If it does boil in go in the reservoir then yes...your engine is getting hot and the antifreeze is boiling.

When the antifreeze boils, it's probably because your thermostat is stuck closed. That means the thermostat isn't letting water circulate through the radiator to get cooled. Thermostats are cheap...no more than $30 I'd say for most cars. Changing them is pretty easy too as they are usually right at the top of the engine. A mechanic may charge $100 to change it....but it's an easy job on most vehicles requiring just a couple sockets/socket wrench.

You don't add it to the radiator , you add it to the plastic surge tank !
Fill the cooling system through the surge tank with a mixture of ethylene glycol antifreeze and water. The mixture must be at least 50 percent antifreeze, but not more than 60 percent antifreeze for cold weather operation. Fill the surge tank to the specified MAX fill mark on the outside of the tank.

Drain radiator, remove thermostat reconnect housing, fill radiator halfway with water add radiator flush it's by Preston fill up with water start engine run for 20 minutes , drain radiator replace thermostat fill radiator with 50/50 mixture of antifreeze and water run engine and top off radiator as needed

My turn to guess!
If your antifreeze is 50%-50%, it should't have frozen up. Can you get enough to check it with a hand-held meter?
First suspicion is the thermostat has stuck, hope it is not a head gasket.
After the engine is cooled to cold, take of the radiator cap and fill the radiator with water.
This is temporary because coolant is expensive.
Turn on the heater full blast and leave it on.
Start the engine, STAND BACK, and have a water hose or container so you can quickly fill the radiator if it goes down.
If the water blows up out of the radiator, you'll need to change the thermostat, it is stuck closed. (Cool engine first).
If radiator blows up after a new thermostat, next is a blown head gasket.
When car becomes happy, drain out enough water ( usually about 1 gallon) to add straight antifreeze, not 50/50 mix.
Be Blessed

check the bottom of the radiator. there should be a drainplug. loosen drainplug. then refill with a 50/50 mix of water and antifreeze, unless it comes premixed. If no drainplug, loosen lower radiator hose and fill

Hi there!
First.- with the engine off and cool, put a flush and drain radiator cleaner run the engine for 10 minutes, turn it off, let it cool down.
Once the engine is not too hot, open the lowest hose of radiator while you put water in the main mouth of radiator.
Once you see the water flushing clear, put the hose back and then fill it with special GM antifreeze, (the one is orange color) put all gallon into it and the rest of water, LOOK FOR THE ONE YOU CAN ADD WATER, THAT'S THE BEST FOR YOUR VAN... Good Luck!

Try checking your antifreeze levels. If you antifreeze tank is low try filling it to the "Fill" or "Full" level. If your antifreeze tank is empty, remove your radiator cap, (make sure the engine has cooled off. If you try to open it while it's hot, you could get sprayed with hot antifreeze) and fill the radiator slowly. Then refill your antifreeze tank. Remember to always mix the antifreeze with water (50/50 mix) for full protection.

On the 4 cylinder you will need 1 1/4 gallons of antifreeze mixed with an equal amount of distilled water for a 50/50 mix. On the V6 you will need 1 5/8 gallons of antifreeze mixed with an equal amount of distilled water for a 50/50 mix. Make sure and use the correct type antifreeze.

The anti freeze is poured into the radiator water and it is necessary as the water should not freeze when in cold weather which can cause serious damage to the parts sepccially the water pump, radiator, engine water jackets/ ports..

a radiator flush chemical may be a bad idea if the radiator is rusted up inside.drain out as much as you can, fill with distilled water only, then idle the car till it is at full operating temp. then drain the water and do the same thing one more time. after that, fill with your 50-50 mix of antifreeze/water and that will be about as clean as you can safely get it.