My 2000 jeep grand cherokee has an overheating problem, replaced radiator ,hoses and thermostat , but still runs hot

I don't know how did you test your radiator but if you apply below steps you can clarify your problem easier.

If you want to test your radiator:
A) Park your car (it takes more longer to get real temperature values, if the car is moving)
B) Start the engine (don't forget to engage handbrake)
C) Wait around 10 to 15 minute
D) If your top radiator hose gets hot and bottom radiator hose gets warm; your radiator is functional. (In few minutes your radiator fan suppose to work)

If bottom radiator hose is still cold, it means there is a problem at thermostat. If you see any leakage at thermostat housing at the end of above step C, you need to renew thermostat housing gasket too. Even if you buy new thermostat, i suggest you to test it before assembly. If new thermostat doesn't open enough, your car may run so hot.

If you would like to test your thermostat:
A) Boil water in disposable bowl (thermostat may exposure chemical substances)
B) Put thermostat into boiling water.
C) If thermostat opens totaly, it is ready for assembly.

Apollo's answer likely correct but can also be caused by an internally delaminated hose or severely blocked radiator.
Flow diagram attached-

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You need to go back to the fan relay you replaced and inspect the terminals closely for overheating and damage.

you may need a head gasket. a shop can use an indicator dye to tell if there is a combustion chamber leak that may only be aparrent when the vehicle is hot.

1. On 2000 Jeep Grand Cherokee 4.7L V8
2. Remove lower radiator hose clamp and lower radiator hose at thermostat housing.
3. Remove thermostat housing mounting bolts, thermostat housing and thermostat.

2000 Jeep Grand Cherokee 4.0l v6Note:on the In-line 6 4.0L model the thermostat housing is mounted at the top of the engine block next to the water pump.

Sounds like your thermostat is stuck closed. Shouldn't be more than a $20 part from autozone and is simple to replace. Follow your top radiator hose to the motor and it will connect to your thermostat housing. Disconnect the hose (antifreeze will run out) unbolt the housing, and replace the old thermostat. Refill radiator and bleed the system.

sounds like one of two problems your fan is not working properly or you radiator is particularly restricted

check all fuse and relay pertaining to the ignition system, make sure all hose are good and the radiator is good, check that thermostat, make sure the fan are working. for the head gasket, check for oil and water mixture in the dipstick

Once the radiator fan operates when hot, then that part of the system is fine. It definitely sounds like the radiator needs flushing out. I had this same problem with a taurus and I flushed the radiator out for a good twenty minutes; you should have seen the stuff that came out! Disconnect the lower hose and drain **** then stick the garden hose in the radiator cap. I would surely do this.

Drain the cooling system down a little bit. Remove the upper radiator hose and heater hose from the thermostat housing. Remove the two bolts holding the housing to the head. Remove the thermostat and clean off the old gasket. Install the new thermostat and gasket and reassemble. Top off the cooling system. Run the engine and check for leaks.