Saturday, May 9, 2015

Changing the coolant in my 2009 Sonata

The owner manual specifies that the coolant change as DIY item so I decided to give it a try. The dealer quoted $154 for a coolant flush. I am not sure what is included in that but the Capitol Hyundai in San Jose is not to be trusted. They told me that my coolant is discolored and must be replaced. I actually replaced coolant at 30K and the color of the old coolant was indistinguishable from the brand new coolant that I put in this time.
The gallon of concentrated coolant from a dealer cost $22 and the rest is labor. So I figured that I can do the labor and learn something in the process. The coolant change is very easy but it is time consuming operation.

What you will need

You will need some new coolant, one gallon container of concentrated coolant which you can buy from a dealer or auto parts store. Make sure that you get the coolant that is correct for your car.
You will need 3 gallons of distilled water which your can get at any grocery store. Make sure you get distilled water and not purified drinking water or any other kind of drinking water. You want a water without any dissolved salts.
You will also need a pan to drain the old coolant in to. The capacity of the cooling system is around 6 liters so make sure that your pan can hold more than 6 liters of liquid.
You will need an empty containers to put your used coolant in to. I used empty plastic juice bottles and also the empty bottles from the distilled water. You will need about 3 gallon bottles.
You will need a funnel and you can invest in to spill free funnel that mounts on the radiator. I managed without it but it seems like a useful tool.
You may optionally use a drip pan. I used a large metal pan which I use for changing the oil. Newspapers can be also used to catch any spills.

The process

The process is described in the Hyundai owners manual and is pretty simple.

Remove the front part of the stone guard by loosening 4 or 5 bolts. The plastic stone guard looks like it is one large piece that extends well under the car. In fact the front part is separate and it is held by a few bolts just behind the bumper. Each bolt is recessed so you will need a socket and a ratchet to remove it.

Put a drip pan under the left side of the radiator and put a collection pan on top. Make sure your engine is cold. Turn your heater on. I am not actually sure how to do this as I have automatic climate control. I turned temperature all the way up but I am not sure if it did anything.
Open the radiator cap and then open the drain plug on the bottom left side of the radiator. The drain plug can be opened by hand, you should not need any tools. Do not remove the drain plug completely until you drain some of the liquid, to prevent liquid spilling on the floor.

The coolant will drain in to your drain pan. I collected a little over one gallon of the coolant although the manual indicated that there should be 6 liters of it. I think some of the coolant was stuck in the heater and I do not know how to open it. Unbolt coolant reservoir and simply lift it above the radiator level. The coolant will drain from the reservoir in to the radiator and from there in to your drain pan.

Close your drain plug and refill the radiator with distilled water. Refill very slowly giving the air time to escape. Burp your system as described in the owners manual. After filling with water, close your radiator and run the engine for about 20 minutes until fan starts and coolant starts to circulate. While engine is running empty your drain pan in to prepared containers and close tightly. The coolant is poisonous so make sure your containers have tight lids.

After running engine for a while turn it off and let it cool. It took about 1.5 hours for me. After the engine cools, drain the water from the radiator just like you did with coolant. The water will come out green since it diluted whatever coolant remained in the system. Place this water in to container for recycling, do not pour it on the ground!

Dilute your concentrated coolant with distilled water in proportion specified on the coolant bottle. I used 50/50 since it was recommended for my climate. Do not mix all coolant with water at once, do it in parts. Mix coolant with water and pour it in to the radiator. Make sure to pour very slowly, letting the air escape. The radiator overflows easy if you try to add the coolant too fast. After you finish with the first part of the mixture, mix another part. Repeat the whole process until the radiator does not take anymore coolant mixture. Make sure to squeeze hoses to let the trapped air escape.
Close the radiator and start the engine. Periodically loosen the radiator lid and watch for air bubbles escaping in to the coolant reservoir. After air stops escaping, open the radiator lid and check if you need to add more coolant. Add remaining coolant mixture in to the reservoir and you are done. Don't forget to replace the plastic stone guard.
Recycle collected coolant and water at a recycling center, do not pour it on the ground or in to the drain. Coolant is poison which should be recycled.

It took me about 4 hours total to do this. Most of the time I was waiting for the engine to cool so actual work time is about 2 hours. I am sure that with some experience one can do this much faster.

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