You guessed it... Overheating XJ

Blew a radiator hose (was very old) replaced it, but filled the system with 100% water (my fault) in freezing temperatures and blew a hole in the radiator. Replaced with a used radiator and after a week the Jeep started to overheat, going into the red and when I shut the vehicle off, it was puking coolant out of the overflow bottle cap. New overflow bottle, new cap, new thermostat, still overheating.

Once all the new parts were placed it, it stayed just above 210 and seemed to be running fine, but after 5 miles, I parked it and it spewed fluid from the cap again. Since then, every time I refill it, it spews coolant, not to mention temp going way into the red zone. I just eased back on the amount of coolant and burped the system, and it doesn't spew out (for now) but the temp is in the red, and when I start it from time to time (very intermittent), I get a weird sqealing noise, almost like my horn is going off, for a short time, and then it will stop.

Grrr, any suggestions?

water pump???

I am apologizing in advance for this very basic question but..

How does the water pump operate? The function as far as pumping water....

I have had brand new thermostats not open up before. Simple test, place your thermostat in a pan of water, set it on the stove and watch it to see if it opens up........hate to think you might have a blown head gasket. Check the easy things first.....

Would the thermostat or the water pump not cause the coolant to circulate?

I connected the hose to the upper radiator hose and the water seemed to be flowing quite well

Cooling is pretty simple... Water / Mix flows through the block / head with help from Pressure and the Water Pump... it also flows through the Rad and heater core, when HEAT is Removed from the fluid by Air cooling the fins on the Heat Sink (Rad) anything that blocks or restricts the flow of Liquid, or Air will prevent proper cooling.

If you had a hose come apart, did any chunks end up in the motor ?

Is there any other Trash, debris, or Rust in the block ? If so, Flush it.

Replace the Thermostat with a Good one

Verify proper operation of the Fan (s)

Verify nothing is blocking Air Flow past the AC condenser and the Rad

Water pumps "Normally" Work, Piss, or have catastrofic failure, it it's not pissing, and the shaft does not feel loose, it's probably fine.

The Lower Rad hose shoulf have a Good Spring in it to prevent it from being sucked Flat, this is Often overlooked, and can cause Lots of problems. ~Ace~

I hate to be the one to say this, but it sounds alot like a blown head gasket. Exhaust gases in the coolant can and will cause blown hoses and ruptured radiators, as well as cause fluid to spew out.

Pull the plugs and check for coolant.......and I'm sorry.

new cap
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did you get the 16 Lber or the 13. Have it tested.