How long does it take you to do coolant flush?

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This weekend I'll be changing the coolant for the first time on my daughter's 2011 Kia Soul w 1.6L engine, it's LONG overdue. I know to do the flush I'll need to drain, refill with water, warm up the engine, then let it cool again to drain and repeat until clear. My question is, how cool do you really need to let it get before you take off the radiator cap? Unless it is piping hot I would think if it's a little hot still it'll just vent as soon as I crack the cap in which case I know not to go further. The reason I'm asking is if I need to drain and fill 3 or 4 times and each time I have to let the engine completely cool off it's going to take a long time (it's already warming up here in Phoenix). I'm curious if I can cut some corners on the cooling of part. I'll also need to make sure I get all the air out really good while I have the car before I give it back to my daughter, I won't have much ability to check up on it too often. Fun story............when I was a kid I saw some folks take the radiator cap off an old pickup truck while it was hot. As soon as that cap let go there was a geyser of steaming water about 8 feet tall. Crazy hillbillies...........lol I still think about that to this day whenever I deal with radiators. And I'm 50.
 
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You can eliminate the need to do repeat drain/fills (the "half life" method) if you remove the thermostat (just temporarily) and disconnect the lower radiator hose. This method makes it difficult to put only distilled water in the system but gets you a very thorough flush as a trade-off. Supposedly modern coolants have additives to combat scale buildup so as long as your tap water is fairly neutral then it shouldn't be a major concern. In my case, I removed the thermostat and reconnected the housing back together temporarily with a paper gasket. Then remove the lower radiator hose at the radiator and swivel it out of the way. Put a garden hose into the lower hose so that it will feed clean water to the pump. Since the tstat is out, once the engine is started (with heater on HOT to clean out the core), it will cycle clean water through the system and dump it from the lower radiator opening. Put a catch basin to collect the old coolant. Only takes less than a minute before you start seeing clean water. Kill the engine, reconnect the thermostat and hoses, drain the radiator or overflow and put in 100% concentrated coolant at half the rated capacity of the system. Fill the difference with water. This gets you a perfectly clean system with exactly 50/50 mix. You will still need to burp the system after.
 
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How often does Kia say to do this? I thought most OEM's were using long life coolant, like 5 years or so. I have to doubt that the system is full of scale and crud. Just a simple drain and refill is going to renew the corrosion inhibitors and keep things from going bad.
 

MoreCowbellAz

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The manual says change it at 30k. This one's coming up on 90k, so way overdue. I haven't looked yet to see if there's any scale or crud visible, my guess is it may not be too bad but nevertheless I don't want it to go any longer. I know it's not full of tap water at least which is good because our water here is absolutely full of minerals, totally hard water.
 
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I just drain the block and radiator and refill. Second refill on my 04 V6 Camry. Cooling system looks new. Took my two days last August as I also replaced the thermostat. Took my time because I'm slow. Probably a two hour job for a younger man. Regards
 

MoreCowbellAz

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Yeah my first thought was just drain and fill and be done with it but then everything I was reading talked about a flush too. Maybe it's the same debate as with ATF, I just do drain and fills there, no flush. This coolant change is just part of my weekend list of oil change, spark plug change, PCV, and coolant. None of that stuff is tough but I also don't want to make the job bigger than it needs to be. I tend to work pretty slow and carefully.
 
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This is part of your weekend work? Then you can definiately do the coolant drain/refill. Run it, run the heater hot to also get the heater core, get the coolant up to temp then while you take care of the other business, let the coolant cool and repeat again when you are done with everything else. Sounds like a long rewarding weekend, hopefully your daughter gets you food. smile
 
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Originally Posted By: Doog
I never do a flush....in over 40 years I have only done drain fill when the engine is cold. if you are worried about not getting it all...do two drain fills one week apart. To get the air out use a Lisle funnel. http://www.amazon.com/Lisle-24680-Spill-Free-Funnel/dp/B00A6AS6LY
HIGHLY recommend using this funnel system. I did use this on my 08 nissan Altima which was up on ramps as I had to replace some hoses and clamps. These Altimas are known to be hard to bleed all the air out of the coolant system. Using this funnel I seen and felt very confident that all the air was bled.
 
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If you know the system is filled with OEM coolant and there is no chance anybody could've topped it off with some generic stuff, then a radiator drain and fill with the OEM coolant will suffice. But if the original coolant looks dirty or was mixed with generic coolants that it would be best to flush all the coolant out with distilled water and refill with the coolant of your choice. On my Mazda 3 it took me 4 radiator drain and fills to get the water to be almost clear. I run the engine long enough to open up the thermostat and then gave it few minutes to thoroughly mix. This way the system never fully pressurized and when I removed the cap, only a small hiss would come out. Then I waited maybe 5 minutes for the coolant to cool off a bit and drained it hot, just as I would drain hot oil. It worked quite well and I think I spent about 2 hours doing it. Oh, and for the final burping, I kept the pressure cap off and revved the engine at about 2k rpm (using a broom stick jammed between the seat and the gas pedal) until the coolant level stopped dropping.
 
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Originally Posted By: MoreCowbellAz
I'm curious if I can cut some corners on the cooling of part.
Yes, absolutely. There are two types answers to questions like this. The politically correct "safety" answer and the realistic answer. I just unscrew the plastic drain plug and let the hot water drain out. You would be performing maintenance for a week if you let it cool completely to surrounding ambient temperatures.
Originally Posted By: MoreCowbellAz
I tend to work pretty slow and carefully.
You sound like me... I don't mind "cutting corners" to save some time, but never at the expense of my car. Distilled water flushes would be my choice. A garden hose is for your lawn smile
 
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I don't know if this is universally applicable, but I read that if you put your settings on the max VENT/DEFROST setting, it will open the heater core as soon as you start the car instead of waiting until the engine is warmed up. Also, when I did a drain/flush a couple weeks ago, I just left the radiator cap off between the flushes which worked fine. I just had to make sure not to rev the engine too hard while I was warming it up otherwise the coolant would overflow out of the radiator opening.
 

MoreCowbellAz

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I'll just see what it looks like, I figured even if I need to do a couple drain and fill and warm ups that realistically nothing dramatic would happen as long as I don't get the coolant fully hot. I've just never tried it, which is why I asked. I have a couple gallons of Zerex Asian in my garage I plan on using, not sure if it's exactly the same as OEM but it'll be safe to use. Kia's spec is pretty generic for this car, ethylene glycol and that's about it.
 
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Originally Posted By: Chewie
I don't know if this is universally applicable, but I read that if you put your settings on the max VENT/DEFROST setting, it will open the heater core as soon as you start the car instead of waiting until the engine is warmed up. Also, when I did a drain/flush a couple weeks ago, I just left the radiator cap off between the flushes which worked fine. I just had to make sure not to rev the engine too hard while I was warming it up otherwise the coolant would overflow out of the radiator opening.
My cars did just that. When I set the temperature to max the heater valve opened without engine running. When I flushed coolant in my cars I always set temp to max to flush the heater core.
 
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On a 2011, why are you bothering with a flush? Just drain the rad and refill it with some Asian HOAT coolant. Boom. Done.
 
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MoreCowbellAz

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Well right or wrong my thought was a) a flush would be easy and b) a more complete coolant change would be beneficial given the fact that it's gone 3 times longer than mfr spec. I would think 90k on coolant that was meant to go 30k means that there's nothing remotely "good" about it anymore, so the more that gets removed the better. I'm not married to the idea, but that's what I was thinking. I don't plan of doing this again for awhile so I want to do it right.
 
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Drain the system by the Radiator or block drain or whatever.Pour some into a glass jar. What does it look like? If it is loaded with sediment, flush it. If not, you dodged a bullet and there's no need to flush. Get as much of the old coolant out and replace it with new. Just curious, what other intervals should you be checking on this chariot? grin2
 
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