I replaced radiator and radiator fan also thermostat in 2000 grand jeep cherokee limited edition,and fan wont run jeep runs hot.2 mnths ago i replaced relay under passanger headlight.Help?????

If your thermostat is bad, it will cause the ecu to keep the fan running at high speed since the engine is remaining hot from limited coolant flow. Have the thermostat checked and changed if it has never yet been replaced.

Is the fan working properly? Is the radiator flowing correctly? Does the rad cap hold the proper pressure?

If it is the 4.0 engine there have always been bad to have a cracked head,right between the valves in one of the cylinders.

Could be a several things, start with the easiest first,

1. Thermostat (DIY for under $10.00)
2. Radiator Fan relay (DIY for under $50.00)
3. Water Pump (DIY for under $70.00)
4. Bad fan motor

Does your radiator fan run when AC is on or when engine is above 200F?

Check your radiator for external and internal obstructions (leaves, bugs etc on the a/c condenser or leaves between the condenser and radiator, rust or calcium deposits inside the radiator core all cause loss of heat transfer)
Also make sure that the system is full and that the electric fan and the clutch fan are operating properly. (electric fan should come on just above normal operating temp and clutch fan should not be "freewheeling" above temp either)
Note: If you need to have the radiator flushed, do it separately from the engine. especially the inline 6 and 4 engines rust up inside and if the system is flushed with the radiator connected, the debris will pack up inside it and actually can worsen the condition.

Either your temperature sensor is unplugged or it has failed and is giving you that reading. (most likely cause...if not, start checking wiring from the sender and make sure any electric cooling fans are plugged in as well.

Radiator removal is not that difficult but too long to write out. Pretty much it involves removing the brace above the radiator and any fans, hoses and lines attached to it. When re-filling do so with heater on full hot to allow coolant to circulate fully through system. I prefer to run engine to the point that temp is at about 200, then turn it off for a few minutes, the thermostat will then open and you can re-start and begin filling again.

I don't know of any real proceedure, Just make sure its full and there is no air traped in the system, If there are any bleeders like around the thermostat housing, or any where in the cooling system open them up while you fill it to let any air to excape If not just fill radiator untill your sure you can't get any more in it before you start it.

First of all make sure there are no air pockets in motor.
Run vehicle with radiator funnel or if don't have one run with cap off until top hose is hot.
If top hose isn't hot then the thermostat is not opening, need to replace. and repeat bleeding procedure.
If it overheats it builds up pressure and causes overflow cap to relieve pressure.

WORST CASE SCENERIO:
water pump is bad not allowing enough flow through out the vehicle.