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Step 1
Open the radiator cap with the engine cold.
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Step 2
Crawl under the front of the car and look at the bottom of the radiator. Find the radiator "drain cock" (also called the radiator petcock). The drain cock is a small plug or T-shaped bolt located at the bottom of the radiator. Sometimes it's plastic.
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Step 3
Place a large pan - 5 gallons or so - under the radiator. Open the drain cock with your hand or an appropriate-size wrench. Allow the radiator to drain into the pan.
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Step 4
Close the drain cock.
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Step 5
Refill the radiator with water until the water is at the top of the radiator or just visible.
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Step 6
Replace the cap.
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Step 7
Run the engine for 5 minutes to circulate the clean water.
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Step 8
Stop the engine, allow to cool slightly and repeat steps 1 through 4.
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Step 1
Add a mixture of 1/2 water and 1/2 antifreeze to the radiator. Fill it right up to the top.
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Step 2
Fill the overflow/coolant reservoir with the same 50-50 mixture.
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Step 3
Leave the radiator cap off, turn the engine on, and let it run until the radiator "burps." There may be pockets of air trapped in the system: You'll see the coolant level drop and may see a large air bubble come to the top as the system burps. Be sure to keep an eye on the temperature gauge throughout this process.
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Step 4
Refill the radiator to the top and the coolant reservoir as needed.
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Step 5
Put the radiator cap back on.
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Step 6
Add more coolant if the engine runs hot after this procedure - there may have been another pocket of air that burped.
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Step 7
Put the old coolant and water in plastic jugs using a funnel.
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Step 8
Dispose of coolant properly - don't pour it down the drain or sewer. Many service stations, repair shops and parts stores will take it so it can be recycled, or you can take it to a recycling center.
Comments
TheLittleGuy said
on 8/3/2008 Is coolant and anti-freeze the same thing?
jpwhickson said
on 12/12/2007 Thanks for the article it really answered a lot of questions. Now I've got to figure out how to drain water completely from the radiator.
magic487 said
on 11/27/2006 Distilled water should be used in the formula, as it is free of the minerals in tap water that could denature the coolant mixture and prevent it from properly doing its job.
Anonymous said
on 1/26/2006 Older Subarus (and possibly newer ones) have two radiator caps. You should use the one on the engine to fill the coolant, and not the one on the radiator. Usually, the one on the radiator has a metal bracket preventing you from opening it.
Anonymous said
on 1/25/2006 When refilling after flush, the thermostat will take longer to open if the top radiator hose has been drained because it has no water sitting on it.