My 04 jeep grand cherokee is smoking from the radiator. the radiator fan doesn't appear to be running. i've had to put more and more coolant in the resivior because it keeps going right through it but i see no leaks. it also looks like there are drip spots of coolant fluid on top of the radiator. the temp gage is running just a smidgen over half way. help?!

Low coolant level?

Brian, I also replaced my radiator and no benefit, it was defective.reinstalled new one; shroud was broken, and replaced. Remember replace your radiator shroud, it must be replaced for directing cooling air over engine. Check what type of anti -freeze your using,there is a difference, and ratio of "mix", Check radiator cap pressure, and temperature of thermostat. ? electric fan cooling, or mechanical? If electric, has 2 settings high and low, could be defective in one or the other (has a relay module somewhere, test it for operational order both high and low.Check your oil make sure you don't have a blown head gasket, . it doesn't take much loss of coolant to lessen pressure and heatup, can sometimes burn coolant out of exhust pipe as water. Oh and make sure you aligned your new thermostat withnotch on its housing and installed correctly. Had a similar problem, I can't say exactly which corrected it, but I did them all and so far problem has not recurred, did change to high temp thermostat. I was actually thinking of getting a new Jeep, but now this one has a new problem, and its a real test of will power, I believe they've made the Jeep with the intention that no-one other than their certified mechanics should work on them. they never considered anything like a national disaster , where there would be no mechanics to work on them, and we might have to do it ourselves, do you realize how sensative the PCM is and how much they cost? if you can even get one?

It could be a fuse or a fan relay that has blown or a faulty coolant temperature sensor or fan motor.

Did you replace the thermostat also?

Sounds like some type of blockage in the system.
with the car cool open the radiator cap, start the engine to see if the coolant has flow.
Even though you just put in a new thermostat it can still be bad,I've had this happen to me a few times.
If the flow seems slow to nill you can also try removing the thermostat all together and giving that a try.
You can test the thermostat in a boiling pot of water.
If ir is totally not the thermostat then there could be a few cooling chambers blocked in the radiator.
This can be repaired in most cases by a "Rod out" at a local radiator shop.
I think the problem is more twards the thermostat for the reason you stated about your heater.
good luck,Gary.

Are you sure the radiator fan is kicking on?

That vehicle has a known problem with fan relays....

The rise in engine temp after replacing the radiator and thermostat could possibly be caused by air pockets trapped in the cooling system. You will need to run the engine with the radiator cap off and let the air escape. DO THIS only when the engine is cold, and let it build up to temp. Coolant will over flow during this process, but eventually coolant will need to be added once the air is released.

Yes, cause that sensor operates the electric cooling fans by the radiator, if those fans or fan don't come on, the radiator can't cool down as quick and causes the engine to run hotter.

Run the car with the radiator cap off. Make sure the radiator is topped off with coolant or water will do just fine. While the car is running look in the radiator neck and check if there are bubbles coming out.
Maybe bad head gasket.

The fan sensor is in the radiator.