You should drain, flush and refill the radiator and cooling system on your Jeep Liberty every 30,000 miles or every two years, whichever comes first. The radiator's upper hose is the more easily accessible of the two; since the coolant runs from the engine to the radiator through this hose, focus on the fitting for the upper hose and radiator when you flush the system. The exact step-by-step process for flushing the system can vary depending on the type of engine your Jeep Liberty has.
Drain the engine coolant: Place a large container under the radiator drain fitting and open the fitting so the coolant will drain out. If the Liberty has a V6 engine, drain the remaining coolant from a second drain fitting at the engine block. Tighten the drain plugs afterward.
Unbolt and remove the thermostat housing from the engine using a wrench--tap the housing with a small rubber mallet if it is stuck. Remove the thermostat from the engine, then reconnect the thermostat housing without the thermostat.
Disconnect the upper radiator hose: Loosen its hose clamp with pliers. Insert a garden hose into the inlet the hose was connected to.
Turn on the hose and look for the water to come out of the disconnected radiator hose. Let the water run until it comes out completely clear, then turn off the water and remove the hose from the radiator inlet.
Reconnect the upper radiator hose using its clamp. Reinstall the thermostat, removing the housing so you can connect the thermostat to the engine, and then reinstall the housing with its bolts.
Fill the radiator with a fresh 50/50 mix of water and antifreeze--fill it slowly until the coolant reaches the base of the filler neck, then fill the reservoir to the "cold fill" mark. Run the engine with the radiator cap off. When the engine reaches operating temperature, the thermostat should open. Fill the radiator completely with 50/50 coolant solution.
