Engine coolant (antifreeze) comes in many varieties (green, yellow, orange) and concentrations (premixed and concentrate). Using the right kind of coolant is critical to the longevity of your engine and cooling system.
So before you start draining the first drop, check your owner’s manual and buy the proper coolant for your vehicle. If you want to save cash on coolant, buy the concentrate and mix it with distilled water according to the directions on the coolant bottle. Never use tap water in your cooling system. The minerals will settle out and attach themselves to the radiator cooling tubes, clogging them and reducing the entire system’s ability to keep your engine cool.
Most DIYers start draining the cooling system by opening the radiator petcock. Bad move. Radiator petcocks are made out of plastic and usually break. Instead, disconnect the lower radiator hose and let it drain until it stops. Then remove the drain plugs from the engine (consult a shop manual for their location). Once the engine is fully drained, replace the drain plugs and reattach the radiator hose. Fill the system with the new coolant. On many late-model vehicles, you’ll have to add the coolant to the overflow bottle. Be patient; it takes a long time for the coolant to enter the system through that smaller hose. Or, if you really want to speed things up, buy the DIY version of the filling tool the pros use (UVIEW 550500 AirLift II Economy Cooling System Refiller; $85 from Amazon.com.) Simply attach your compressed air hose to the tool and pull a vacuum on the entire system. Then close the valve and attach the tool’s fill tube to a bottle of mixed coolant. It’ll suck the new coolant into the system. Repeat the procedure a few times and your system will be full. And, you won’t have any air pockets to bleed.
— Rick Muscoplat, Automotive Editor
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