Cooling System Flush and Repair
Radiator coolant is usually a 50/50 mixture of anti-freeze and water. This coolant keeps your engine operating at the proper temperature. (Caution: coolant/anti-freeze is a poisonous substance. Do not allow this liquid to come in contact with your skin, mouth, eyes or any other body opening. Follow medical procedures on container if this should occur. Take any used anti-freeze/coolant to a regulated disposal site.)
When the radiator coolant becomes worn, dirty or contaminated, it is time to replace it with new. Most owner's manuals recommend changing coolant every 30,000 miles. This is also a good time to check the condition of your hoses and the radiator itself.
The temperature of vehicle should be cold: in other words, you should allow your engine to cool for several hours or overnight before beginning this procedure. With the ignition in the off position and the parking brake applied, grab a container that is large enough to catch about two gallons of fluid. You can either open the cooling system access port or disconnect the lower radiator hose, and allow the coolant to flow out of the system into your two-gallon container. While the fluid is draining, check the condition of the radiator and heater hoses. Check the connections to make sure they are tight. Examine all hoses to see if any are cracked, soft or punctured; if you find any of these conditions, replace the hose(s).
Check for leaves, dirt or other debris that may be blocking the front of your radiator. Remove any that you find with a soft vinyl brush or rag. Also check the radiator for rust and/or corrosion. If you see any signs of rust or corrosion, which will interfere with the radiator's ability to cool your engine, take it into a radiator repair facility to have it recored or repaired.
After the coolant has drained, move the heater control to the full "on" position. Remove the radiator reservoir cap and fill the system with water. With the reservoir cap still off, start the motor and rev it a few times. Run the engine until the thermostat opens. (You can determine this by monitoring the radiator hoses. When they begin to feel warm, the thermostat has opened.)
Allow the motor to cool completely and drain out the water. If the water is not clear, repeat the foregoing procedure until it is clear and free of contaminants.
Once the water is clear, follow the procedure above and fill the system with a 50/50 mixture of anti-freeze and water. Squeeze the upper radiator hose to remove any air from the system. Add more of the coolant/water mixture until you have reached the "hot" level on the reservoir.
With the engine still running, turn on the heater blower motor and turn up the heater to maximum. If you feel warm air, it indicates you have purged all of the air out of your cooling system.
Now your engine coolant/anti-freeze is fresh and ready to do the job it is supposed to do - cool your engine.