Coolant change screw-up?

W

Waunakee

Member
I watched a few videos online regarding how to change the FL-22 coolant in a CX-5, and not one of them showed anything more than draining the fluid from the radiator, then refilling the radiator with water to sort of flush it out, running the engine to temperature, and draining it again, repeating that process twice. A few sites even recommended not power flushing the system, so I decided to just change the coolant myself.*

I then did exactly that, refilling it twice, but only 4 quarts of coolant were drained each time, After adding*a gallon of the pre-mixed Mazda FL-22 coolant to top it off, I then noticed that*the manual says that the total capacity is 8 quarts! Therefore, every time I refilled the system, I was diluting the coolant that remained in the engine (about 4 quarts of fluid).

Doing the math,assuming a 50/50 mix of coolant and water and perfect mixing of water and coolant, the first time I drained the radiator,*I left 4 quarts of 50% coolant/50% water (i.e., 2 quarts of each) in the engine. After refiling it with 4 quarts of water, I then had 2 quarts of coolant and 6 quarts of water. Repeating this process, I was down to*1 quart of coolant and 7 quarts of water. Finally, draining the radiator and*adding 4 quarts of the correct 50/50 mix, I now have 2.5*quarts of coolant and 5.5 quarts of water, or a 31% coolant/69% quarts of water mix.

Since I live in Wisconsin and air temperatures (not the wind chill) can range from -20 F to 100 F, I'm concerned that this will not be sufficient. Should I be concerned? Is there anyting I can do, short of taking it to a garage and having them do a vacuum flush? The FL-22 only comes premixed, so I can't take out some of the current mixture and add pure coolant.
 
Waunakee said:
I watched a few videos online regarding how to change the FL-22 coolant in a CX-5, and not one of them showed anything more than draining the fluid from the radiator, then refilling the radiator with water to sort of flush it out, running the engine to temperature, and draining it again, repeating that process twice. A few sites even recommended not power flushing the system, so I decided to just change the coolant myself.*

I then did exactly that, refilling it twice, but only 4 quarts of coolant were drained each time, After adding*a gallon of the pre-mixed Mazda FL-22 coolant to top it off, I then noticed that*the manual says that the total capacity is 8 quarts! Therefore, every time I refilled the system, I was diluting the coolant that remained in the engine (about 4 quarts of fluid).

Doing the math,assuming a 50/50 mix of coolant and water and perfect mixing of water and coolant, the first time I drained the radiator,*I left 4 quarts of 50% coolant/50% water (i.e., 2 quarts of each) in the engine. After refiling it with 4 quarts of water, I then had 2 quarts of coolant and 6 quarts of water. Repeating this process, I was down to*1 quart of coolant and 7 quarts of water. Finally, draining the radiator and*adding 4 quarts of the correct 50/50 mix, I now have 2.5*quarts of coolant and 5.5 quarts of water, or a 31% coolant/69% quarts of water mix.

Since I live in Wisconsin and air temperatures (not the wind chill) can range from -20 F to 100 F, I'm concerned that this will not be sufficient. Should I be concerned? Is there anyting I can do, short of taking it to a garage and having them do a vacuum flush? The FL-22 only comes premixed, so I can't take out some of the current mixture and add pure coolant.
Click to expand...
Thats why I prefer to get pure coolant when I do coolant change. When we flush the coolant system with tap water or distilled water, we can add half of the specified coolant capacity with pure coolant at first as the coolant left in the system is mostly plain water. Then fill up with distilled water.

I do remember my Mazda dealer does sell OEM pure FL-22 coolant. If not, you may drain the fresh coolant, and add 50% FL-22 coolant, and do it acoupld of times, which should bring up the percentage of FL-22. Of course thiss expensive to do, as the OEM 50% FL-22 coolant costs at least $20 per gallon.

The best is to find coolant drain on engine block if theres one on CX-5.
 
MyFirstMazda said:
Get one of the cheap testers, an see how cold your mix is good for.
Click to expand...

I had an old, cheap type of tester with floating balls, but none of them floated, even with the new FL-22 mix. I think the specific gravity of FL-22 must be very different from the old polyethylene glycol.
 
yrwei52 said:
That*s why I prefer to get pure coolant when I do coolant change. When we flush the coolant system with tap water or distilled water, we can add half of the specified coolant capacity with pure coolant at first as the coolant left in the system is mostly plain water. Then fill up with distilled water.

I do remember my Mazda dealer does sell OEM pure FL-22 coolant. If not, you may drain the fresh coolant, and add 50% FL-22 coolant, and do it acoupld of times, which should bring up the percentage of FL-22. Of course this*s expensive to do, as the OEM 50% FL-22 coolant costs at least $20 per gallon.

The best is to find coolant drain on engine block if there*s one on CX-5.
Click to expand...

There apparently is no coolant drain plug on the engine block.
 
Waunakee said:
I had an old, cheap type of tester with floating balls, but none of them floated, even with the new FL-22 mix. I think the specific gravity of FL-22 must be very different from the old polyethylene glycol.
Click to expand...

I just tested my antifreeze with my cheap old antifreeze hydrometer, it showed above the recommended freeze point and above the recommended boiling point. My hydrometer says 'Tests all ethylene glycol anti-freeze coolants' and FL22 is a long life ethylene glycol antifreeze. Your mix might have too much water in it, if non of the balls floated or it might be broken. My meter is the type with a needle.
 
Agreed: FL-22 density is a bit higher compared to ethylene glycol, but close enough that a hydrometer should work. But I hate to say that a simply hydrometer needs to be combined with temperature for anything near accurate.
Your goal is to get 50% FL-22 coolant to water. Living in MN (like WI) you need protection down to -35F range to be comfortable. You can get close enough with your diluted FL-22, but that would take 3x drain refill = 3 gallons of premix and that's expensive.
What I would do: Do 1 drain / refill with a gallon of Pentosin Pentofrost A2 is a dark green concentrate. Your refill will be the Pentofrost A2 diluted to around 70% coolant (a little less than 3 qts Pentofrost and 1 qts water).
The nice thing about Pentofrost A2 is that it is available at some auto part stores and Rockauto.
Other options for FL-22 concentrate (but more expensive or harder to find):
Ravenol concentrate available through Amazon
Ford (Motorcraft) concentrate: VC-10-A2 (specialty green)
 
Last edited:
FL-22 is a super long life coolant... your car is less than 10 years old... did you already put 120k miles on the car?

the videos you saw were likely meant for CONCENTRATED coolants for OTHER cars, which is not what FL-22 comes as from the dealer... they only come premixed, and you had ruined the mix and longevity of your coolant due to impurities (tap water has minerals that affects the life of coolant)

to get it right away, you'll have to either remove various coolant hoses or parts to let what's in the engine or heater spill out, or take the car to the dealer and let them flush the entire system for you and replace with the correct mix FL-22

had you asked all of us here, or reading the shop manual, you would've known the youtube videos didn't apply to what you needed to do
 
davmac said:
Agreed: FL-22 density is a bit higher compared to ethylene glycol, but close enough that a hydrometer should work. But I hate to say that a simply hydrometer needs to be combined with temperature for anything near accurate.
Your goal is to get 50% FL-22 coolant to water. Living in MN (like WI) you need protection down to -35F range to be comfortable. You can get close enough with your diluted FL-22, but that would take 3x drain refill = 3 gallons of premix and that's expensive.
What I would do: Do 1 drain / refill with a gallon of Pentosin Pentofrost A2 is a dark green concentrate. Your refill will be the Pentofrost A2 diluted to around 70% coolant (a little less than 3 qts Pentofrost and 1 qts water).
The nice thing about Pentofrost A2 is that it is available at some auto part stores and Rockauto.
Other options for FL-22 concentrate (but more expensive or harder to find):
Ravenol concentrate available through Amazon
Ford (Motorcraft) concentrate: VC-10-A2 (specialty green)
Click to expand...

I think FL-22 is 55/45 mix
 
TheMAN said:
I think FL-22 is 55/45 mix
Click to expand...

Thanks. That's good input to the equations to calculate the concentrate to fix the OPs problem. If the goal is 55% coolant then do a drain and refill with 80% concentrated mix = 100 oz pure coolant and 28 oz water - preferably distilled water.
I guess it is up to the OP, but the issue can be fixed for about $30 (includes a gallon of Pentofrost A2 and gallon of distilled water) and 1 more simple drain and refill.
 
to anyone else reading this thread.... there is usually NO reason to "flush" your cooling system, unless it has serious build up/neglect or rust... the likelihood of this is very low, because these engines are all aluminum, as are the heater block and radiator... if you think that flushing your cooling system makes you feel better, because you got all of the old stuff out, you're doing more harm when you're pumping it full of tap water, which can be hard enough that it adds build up to the cooling system, affecting its efficiency, and most certainly can affect the service life of the antifreeze

manufacturers account for this, but also account for the fact that you can never drain every last drop out of the system, so their subsequent change interval is less than the initial one... if you do it right, and not flush, but spend more money by changing the coolant a couple of times at the same time, you can likely (but hard to prove) get 10 years or 120k interval, like originally... not worth the trouble though
 
Agreed. I'm convinced for the DIY and really anyone the simple drain refill is the best way to refresh fluids: coolant, transmission, power steering. Every fluid wears out over time. Around 100K miles refreshing fluids is a good idea. Make yourself a calculator with the total capacity and the drain capacity to figure out how much of your fluid is new after each refill. When you drain 1/2 the capacity each time a simple drain and refill 3x and you finish with 87.5% new fluid. For most people the process is simple enough and cheap enough to keep an old car for a long time.
 
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