The coolant in a Chevrolet Van is a 50/50 mix of antifreeze and water. The coolant is circulated by the water pump, which is mounted on the front of the engine. Coolant flows from the engine to the radiator through the upper radiator hose. As water flows down through the radiator, heat is drawn off the coolant by air pulled across the radiator by the engine fan. The coolant then returns to the engine through the lower radiator hose, where it circulates through the engine block, cylinder heads and intake manifold.
Wait until the cooling system is completely cool before beginning this operation. You should wait at least three hours after running the engine.
Rotate the radiator cap counerclockwise until it hits a stop, using your hand.
Wait until the hissing sound stops, if you hear any.
Press down on the cap with your hand. Continue rotating it counterclockwise until the cap can be pulled off.
Clean the radiator cap and neck with water and a clean rag. Scrub away any signs of corrosion.
Examine the coolant by looking through the filler neck. It should be mostly transparent. If it is rust colored, it should be drained and the radiator refilled.
Drain the coolant. Place a waste oil collection pan underneath the petcock valve located on the lower left corner of the radiator. Open the petcock valve with needle-nose pliers. This step is only necessary if there are signs off rust in the coolant.
Check the level of the coolant. It should come up to the bottom of the radiator cap neck.
Fill an empty plastic milk jug half-full with antifreeze.
Fill the other half with tap water.
Screw the cap onto the jug and shake it for about 30 seconds.
Pour the 50/50 mix of antifreeze and water into the radiator cap neck.
Fill the radiator to just below the radiator cap neck.
Insert the radiator cap into the neck. Press down on it with your hand and turn it clockwise until it is tight.
