Jeep Cherokee radiators fail in two ways; they leak or they clog. Both of these conditions lead to overheating. The radiator is easy to change using simple hands tools and can be accomplished by an average mechanic in about an hour.
Begin by removing the air intake box. This will give you access to the electrical connectors as well as the lower radiator hose and transmission cooling lines on the automatic.
Disconnect the electric fan and on pre 1991 models the radiator temperature switch. Remove the electric fan by removing the two small bolts (8MM heads) that connect the fan to the radiator cross member. Lift the fan out.
Unbolt the fan shroud from the cross member and slide it back over the mechanical fan but do not remove it. Use care not to loose the clips that the fan shroud and electric fan bolt to. If they break or get lost, you can get replacements at most hardware stores.
Remove the radiator cross member. It is held in place with six bolts that have 10MM heads. There are also four studs that hold the cross member to the front header. These usually have 7/16″ nuts on them. Remove the two 10MM nuts that hold the cross member to the rubber radiator upper mounts. Tip the cross member up toward the front of the Jeep to remove it.
Some radiators have a drain connection on the lower right side that can be accessed by removing the grill. Alternately, the fluid can be drained by removing the lower radiator hose. Place a bucket under the Jeep to catch the fluid as it drains.
Remove the upper radiator hose. On the automatic transmission Jeeps, there are two cooling lines that have to be removed. Unbolt the upper line at the radiator. This is a flare fitting. Use a ¾ inch wrench to turn the connector.
The lower line is a special quick connect. Often these will disconnect by simply pressing the two exposed parts of the clip in with your fingers. Some later model quick disconnects do not have the finger tabs and you will need a transmission line disconnect tool to pop them loose. Also, sometimes the finger tabs will break and the tool will also be required for these as well. If all else fails, use a dental pick to lift the clip over the ridge on the tube coming out of the radiator.
Remove the rubber mounting pads from the top of the radiator so they can be reused on the new one. Unbolt the AC condenser. Remove the clip that holds lower transmission cooling line.
Remove the radiator by pulling straight up. It is held in place by two pins in rubber bushings at the bottom.
If the Jeep has overheated, it is a good idea to change the thermostat as well. It is easier to change the thermostat with the radiator out but not necessary. Also inspect the hoses and replace any suspect ones at this time.
Transfer the upper mounting pads to the new radiator and install any adapters that it has for the condenser mounting brackets. On pre 1991 models, transfer the temperature switch from the old radiator to the new one.
Slide the new radiator into place making sure that the pins slide through the lower condenser mounts and into the rubber bushing in the body. Reconnect the lower transmission line at the quick connect. Replace the lower radiator hose and tighten the clamp.
Reinstall the flare connector for the upper transmission line. Connect the mounting tabs for the AC condenser. Connect the upper radiator hose and tighten the clamp. Reattach the clip that holds the lower transmission cooling line to the radiator.
Set the radiator cross member back in place. It may help to tip it in down over the front mounting studs to get it into place. If it does not drop all the way down, this means that the radiator is not seated on its mounting pins. Check to see where it is binding before continuing.
Install but do not tighten the six bolts that hold the cross member to the body. Next install the four nuts on the studs at the header. Center the cross member and tighten the bolts and nuts.
Reattach the fan shroud being careful with the mounting clips. The shroud has two lower tabs that fit in slots in the radiator. Reinstall the electric fan and tighten its bolts. It fits in just like the fan shroud. Reconnect the wires to the fan and temperature switch.
Reinstall the air intake box. Install a new air filter if the old one is dirty.
Slowly fill the system with a mixture of antifreeze and water. Let the Jeep sit a moment to see if any air bubbles out. Shake the Jeep form side to side to see if more air will bubble out. On pre 1991 Jeeps without a radiator cap, it is helpful to remove the temperature sensor at the back of the head to let the air escape.
Once you have put in as much coolant as it will hold, start the engine and check for leaks. Allow the engine to come up to operating temperature and shut it off. Once it cools, check the coolant level again. Repeat the process until all the air is removed. Be sure to pay close attention to the engine temperature and do not allow the engine to overheat while purging the system of air.