1999 Other Chevrolet Models replace radiator fluid

The best way to change the coolant in any vehicle also involves flushing the system. Start by parking the vehicle near a water hose away from any animals. Coolant is not particularily bad for the enviroment, but animals like to lick it up and it may kill them, so you will want to hose down the area after to dilute the coolant. Drain the radiator, there is a drain cock at the bottom inside of the radiator on one side. You will have to turn it counter clock wise about 180 degrees. You may skip this step if drain is too hard to reach or stuck. Next, remove the upper radiator hose and place the water hose in the radiator fill neck. Turn on the water and start the engine once the water begins to over fill. Water will flow through the radiator into the engine and out the upper radiator hose. Run the engine until the water coming out is clear, and the engine is at operating temp. Remove the lower radiator hose and alow the system to drain. Remove the heater core hoses on the passenger side firewall, they will be about the same size as a garden hose. Run water through one side and the water will come out the second. Stop when the water comes out clear. You may use an air gun to blow additional water out of the system. You will also need to flush out the over fill resivoir. Remove the small hoses from the radiator and run them down below the resivoir so that it drains and begin flushing with water. Remove as much water as you can from the system, and re-connect all hoses and close drain cock. In you owners manual you can find the capacity of the cooling system, put half this amount of un-mixed coolant in the system. Once you have 50% of the capacity of coolant in the system you can finish filling the system with water. Many vehicles have purge screws in the coolant system that help remove air from the system. Running the vehicle briefly and revving the engine will help also. If you believe you have all of the air out of the system take it for a test drive and get the engine up to operating temp. Stop the car and wait for it to cool. Re-fill the system if needed, and repeat until no more air is in the system.