How to Change the Coolant in Cars

by Contributing Writer; Updated June 12, 2017

Draining the radiator in a Honda car is a straightforward process. Coolant, or antifreeze, flows from the radiator to the engine to prevent overheating. As coolant ages, inert residue builds up and the liquid becomes sluggish. When this happens, the engine in your Honda car does not cool properly. Over time, this can damage the system on your car. Cars differ by year and model, and steps for routine maintenance vary based on the year and engine size of your Honda car. So always check the manual for your model before doing any work on the vehicle.

Under The Hood:

 How to Change the Coolant in a Mazda 3

Turn your engine off and allow it to cool completely. Wait at least 30 minutes prior to beginning the procedure.

Wrap a thick hand towel on the radiator cap and carefully twist it two to three times to relieve pressure. Step away from the vehicle for a few moments. Do not fully remove the cap.

Remove the plastic engine guard underneath the front part of the engine bay. The guard is attached by screws and bolts. Set the engine guard aside to access the bottom portion of the radiator.

Remove the engine coolant reservoir cap to assist the system in draining. Use a screwdriver to unscrew the radiator drain plug. Once the plug is unscrewed, pull on it to remove it. Allow the coolant to completely drain into the pan or container. This should take about 15 to 20 minutes.

Pour a gallon of distilled water through the coolant reservoir to clean out the system. Allow the water to drain into the pan with the coolant.

Replace the radiator drain plug and fill the system with coolant through the reservoir. The Mazda 3 coolant capacity is 7.9 qt., which is approximately 2 gallons. Do not overfill the coolant system. Tighten the radiator cap, but do not tighten the reservoir cap.

Reconnect the negative battery cable with the reservoir cap off. Start the engine and let it idle for a few minutes to rid the system of any possible air bubbles. Monitor your engine operating temperature while the engine is running. Turn the engine off, check for leaks, then replace the reservoir cap and the engine guard.

Items you will need

  • Hand towel

  • Pliers

  • Distilled water

  • 3 to 4 gallon drain pan or container with lid

  • Screwdriver

  • Replacement coolant (50/50 ethelyne-glycol based)

 How to Change the Coolant in a Hyundai Elantra

Allow the Elantra's engine to cool properly if heated or warmed up.

Release the hood latch and open the hood.

Lift the front of the vehicle with a floor jack and then place jack stand under the front frame rails to support the vehicle.

Place the drain bucket beneath the petcock valve of the radiator and then turn the petcock counterclockwise. As the trickle of coolant pours, crawl out from under the Elantra and remove the radiator cap from the radiator. This air pocket will increase the flow of fluid, and checking the position of the drain bucket will be required.

Allow the radiator to drain to a trickle. If desired, to release more coolant, remove the upper and lower radiator hoses (from the radiator) by removing the clamps with a screwdriver or a pair of pliers---depending on the style clamp in place. Position the hoses (once they're removed) to pour into the drain bucket.

Tighten the petcock, replace the radiator hose and then tighten the clamps when the coolant of the Elantra is thoroughly drained.

Lower the Elantra back to the ground.

Place a funnel into the radiator neck of the Elantra's radiator and fill it with the new coolant (hold the coolant jug horizontally and flat while pouring to allow minimal spillage). Be sure the coolant is remixed with 50 percent water. Add the coolant until the radiator will allow no more.

Start the engine of the Elantra with the radiator cap still off and the drain bucket positioned below the radiator cap. This will allow the Elantra to burp any air bubbles in the coolant system to purge out of the radiator and fall into the bucket.

Inspect the temperature gauge of the Elantra during this procedure to assure the gauge does not exceed the "safe" temperature limit. Add more coolant as necessary.

Replace the radiator cap and then test drive the Elantra for 10 to 20 minutes while monitoring the temperature gauge. Shut the Elantra down or turn the heat to full and the fan to full if the system overheats.

Remove the radiator cap again (after the test drive and the engine has cooled down somewhat) and add coolant if necessary.

Items you will need

  • Engine coolant drain bucket

  • Engine coolant (properly mixed with 50 percent water)

  • Funnel

  • Shop rags

  • Floor jack

  • Jack stands

  • Screwdriver

  • Pliers

 How to Change the Coolant in a Honda Accord

Turn the heater control inside the Accord to maximum heat. If you have a digital thermostat, start the car, set the thermostat to 90 degrees and turn off the car.

Open the hood and inspect the engine and radiator. They should be cool to the touch.

Remove the radiator cap carefully by hand. There should be no steam from the radiator.

Move under the car. Place a drain pan under the radiator, then locate and loosen the radiator drain plug, using a wrench. The plug will be at the bottom of the radiator. Let the coolant drain into the pan.

Locate the drain bolt on the engine block. Refer to your manual if you are unsure of the bolt's location. Use the wrench to remove the bolt and washer.

Pull up on the reserve tank, near the radiator, to remove it. Dump the coolant out of the tank (and into the drain pan) and reseat the tank. If your Accord is a six-cylinder model, remove the cruise control and ground control cables before pulling the reserve tank off the radiator. Replace the cables after dumping the coolant and replacing the tank.

Tighten the radiator drain plug once all the coolant has drained out of the radiator.

Replace the washer for the engine drain bolt, and reseat the bolt. Double-check the bolt to ensure it is tight.

Follow the instructions on the antifreeze container for mixing ratio. Mix the antifreeze with distilled water.

Follow the instructions on the antifreeze for mixing ratio. Mix the antifreeze with distilled water.

Loosen the bleeder bolt at the top of the engine, using a wrench. This will only be necessary if you have a four-cylinder model. Tighten the bolt again when coolant leaks out in a steady stream with no bubbles.

Check the fluid level again, and add additional coolant if necessary. You should see the fluid at the edge of the radiator opening.

Turn the car on and let it run until the engine warms. Wait until the fan comes on at least twice.

Turn the engine off and recheck the fluid level. Add additional coolant if required. You still want to see fluid at the edge of the radiator hole.

Replace the radiator cap, and fill the reserve tank to the maximum-level marking.

Items you will need

  • Drain pan

  • Wrench

  • Antifreeze

  • Distilled water

 How to Change Coolant on a Subaru Forester

Raise the vehicle off the ground with a jack and support it on a set of jack stands. Place the drain pan or bucket under the radiator drain petcock on the bottom left of the radiator.

Remove the undercover from the area below the radiator. Remove the radiator cap from the radiator filler neck. Open the drain petcock and allow the coolant to drain into the pan or bucket under the car.

Close the drain petcock after the coolant has stopped flowing from the radiator drain. Remove the jack stands and lower the car back to the ground. Fill the radiator with new coolant, continuing until the radiator will not accept any more.

Close the radiator cap, start the engine and race it to 3,000 revolutions per minute, or RPM, five or six times, then shut down the engine. Wait one minute and then open the radiator cap. Add coolant to the radiator if it is low.

Close the cap and run the engine again, racing it five or six times, then shut it down. Allow it to sit again and recheck the level, adding coolant to fill the radiator if needed. Replace the radiator cap.

Start the engine and run the engine at 2,000 RPM and run the heater blower motor on the high setting. Allow the engine to continue running until the electric fan comes on and then shuts off. Shut down the engine and allow it to cool.

Open the radiator cap and add coolant if it is low. Fill the coolant reservoir to the full mark and close the cap.

Place the heater control on hot and the blower to low. Start the car and race it to 3,000 RPM again. If you hear any water rushing or flowing sounds in the system, continue racing and filling the cooling system from step 5 until you no longer hear the coolant flowing.

Items you will need

  • Jack

  • Jack stands

  • Drain pan or bucket

 How to Change the Coolant in a RAV4

Open the engine hood of the RAV4 by pulling the hood-release lever under the steering column of the vehicle.

Locate the coolant tank in the engine cavity. This is a large, clear tank full of pink fluid positioned in front of the engine on the passenger side.

Place a collection pan with a minimum 5-qt. capacity underneath the coolant tank beneath the vehicle.

Unscrew the lid on the coolant tank. Use a clamp removal tool to disconnect all three of the tubes that run from the coolant tank to the engine. Wait for the fluid to fall from the tank into the drain pan below the vehicle.

Reattach the tubes to the tank. Pour 2.5 qts. of coolant into the tank. Screw the lid back on and close the engine hood.

Items you will need

  • Drain pan

  • Clamp removal tool

 How to Change the Coolant in a C5 Corvette

Set the parking brake and place wheel chocks in the front and back of the rear tires to prevent the car from rolling.

Put on your safety glasses and remove the coolant recovery bottle cap. Do not work on the cooling system when the engine is hot. It’s best to let the car sit for 12 hours before performing this procedure.

Jack up the front end of the Corvette. Place jack stands under the front frame and carefully lower the car onto the jack stands.

Place the drain pan under the lower radiator hose where it meets the radiator.

Use the socket set to remove the radiator hose clamp where the lower radiator hose meets the radiator and slide the hose back, away from the radiator, being careful to immediately aim it down into the drain pan.

Open the petcock on the bottom of the radiator and let it drain into the drop pan as well. You may need to use pliers to open the petcock, but use extreme care when doing so to prevent damage to the petcock or radiator.

Close the petcock after all the Dexcool has drained, then slide the lower radiator hose back on and tighten the hose clamp back down. Do not over-tighten the clamp but tighten it just to the point where rubber begins to squeeze through the slots in the clamp band.

Pour one gallon of Dexcool into the coolant recovery tank then add one gallon of distilled water. Continue to add a 50/50 mixture of Dexcool and distilled water until the fluid level in the tank is up to the cold fill line.

Start the engine and let it warm up with the recovery tank cap off. The coolant level will go down a little as air escapes the system. Shut the car off after one minute and top off with coolant, again using a 50/50 mixture.

Reinstall the coolant recovery tank cap and run the engine for 10 minutes. Check the coolant level: if it has gone down, let the engine cool and then top it off again.

Inspect the petcock and lower radiator hose for leaks. Move the drain pan out of the way, then carefully jack the car back off the jack stands, remove the jack stands and lower the car back onto the ground. Recheck the coolant level again after the next day of driving.

Items you will need

  • Wheel chocks (4)

  • Safety glasses

  • Jack

  • Jack stands (2)

  • Drain pan

  • Socket set

  • Pliers (optional)

  • 2 gallons of Dexcool coolant

  • 2 gallons of distilled water

About the Author

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