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2015 mazda3i AT, 110k miles (mostly hwy)

6 years and 110k miles, I think it's time for a coolant change.

1) do I have to use their FL22 coolant?
or can I use walmart brand 50/50 premixed?

2) any step by step guides?

Thx
 

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2015 mazda3i AT, 110k miles (mostly hwy)

6 years and 110k miles, I think it's time for a coolant change.

1) do I have to use their FL22 coolant?
or can I use walmart brand 50/50 premixed?

2) any step by step guides?

Thx
1. No it is not a requirement to use FL-22. You can use any Ethylene glycol coolant. However, FL-22 is a better product. It has better anti-corrosion properties and lubricates the pump better. I think a new pump costs a lot more than the coolant.

2. Yes there are plenty of guides. Our own DIY subforum has one, Google has loads as does YouTube. The factory service manual is also in our DIY subforum. I'm not about to do the searching for you, so take a look.
 

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I also recommend staying with FL22, as the process for switching coolant types is much more involved. Chemical reactions between different types of coolants can really screw up your cooling system.
 

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I also recommend staying with FL22, as the process for switching coolant types is much more involved. Chemical reactions between different types of coolants can really screw up your cooling system.
A chemical reaction isn't very likely but is still worth considering. FL-22 is still just ethylene glycol antifreeze and water just like cheap coolant. It does have different additives in it however. The owner's manual does clearly state that you can use regular ethylene glycol coolant just fine but are the additives going to react with each other? Probably not but I doubt either of us can say for sure.

The one you're thinking of that reacts terribly is the old GM dexcool. In an effort to make a non toxic coolant, GM made one that uses propalyne glycol antifreeze. That stuff is quite harmless and is in fact in food we eat. It's also a shitty lubricant so they blew water pumps easily. Plus if you mix it with the traditional green stuff it'll turn into a solid gel.
 

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I'd use FL22 or at least something recommended by the manufacturer as suitable for your Mazda, otherwise leave the original FL22 alone. Coolant technology is fairly complex and the wrong coolant can heavily damage your engine -either by quickly turning to gell or by long term corrosion. And don't select coolant by color- it's totally irrelevant to the coolant specification.
 

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The one you're thinking of that reacts terribly is the old GM dexcool. In an effort to make a non toxic coolant, GM made one that uses propalyne glycol antifreeze. That stuff is quite harmless and is in fact in food we eat. It's also a shitty lubricant so they blew water pumps easily. Plus if you mix it with the traditional green stuff it'll turn into a solid gel.
Boy do I know all about that! I bought a '99 ford taurus as a quick flip car. While driving it home it had no heat, and the radiator fans ran continuously. When I looked in the coolant reservoir, there was lumpy black stuff floating around in it. I think someone had thrown green coolant into ford's red coolant. Double-plus un-good! Thankfully, they hadn't added enough to gum up everything completely. I did a complete flush of the coolant system. Then I reverse-flushed the heater core by alternately filling it with water, then giving it a blast of air from the compressor. Blew out black goo, big chunks of scale, and a little rust. Then I treated the whole system with Lime-a-way for a few minutes, just to dissolve a little more scale/rust. Finally I refilled with fresh coolant & distilled water. Fans ran normally and the thing would put out heat like a furnace!

I know that doing all that to the cooling system could have damaged seals or make the heater core leak, but at that point my alternative was to replace the heater core and possibly the radiator anyway, so it seemed like a good risk. I was lucky that the cooling system wasn't irretrievably plugged up and I could clean it up. So my rule is to never mix coolants.

I buy a lot of cars, and I often find people have switched from the factory coolant to "something else" (green, orange, red, pink, blue, plaid...). Identifying what kind of coolant is in a car is often hard, as there's "old" green coolant, and "new" green coolant. Usually, if there isn't a problem with the cooling system and the coolant looks good, I leave well enough alone. But if I have to touch it, I do a complete flush and refill it with factory coolant. On the rare occasions where I can't get the factory stuff, I write what I did use on the reservoir so that the next person knows.
 

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Boy do I know all about that! I bought a '99 ford taurus as a quick flip car. While driving it home it had no heat, and the radiator fans ran continuously. When I looked in the coolant reservoir, there was lumpy black stuff floating around in it. I think someone had thrown green coolant into ford's red coolant. Double-plus un-good! Thankfully, they hadn't added enough to gum up everything completely. I did a complete flush of the coolant system. Then I reverse-flushed the heater core by alternately filling it with water, then giving it a blast of air from the compressor. Blew out black goo, big chunks of scale, and a little rust. Then I treated the whole system with Lime-a-way for a few minutes, just to dissolve a little more scale/rust. Finally I refilled with fresh coolant & distilled water. Fans ran normally and the thing would put out heat like a furnace!

I know that doing all that to the cooling system could have damaged seals or make the heater core leak, but at that point my alternative was to replace the heater core and possibly the radiator anyway, so it seemed like a good risk. I was lucky that the cooling system wasn't irretrievably plugged up and I could clean it up. So my rule is to never mix coolants.

I buy a lot of cars, and I often find people have switched from the factory coolant to "something else" (green, orange, red, pink, blue, plaid...). Identifying what kind of coolant is in a car is often hard, as there's "old" green coolant, and "new" green coolant. Usually, if there isn't a problem with the cooling system and the coolant looks good, I leave well enough alone. But if I have to touch it, I do a complete flush and refill it with factory coolant. On the rare occasions where I can't get the factory stuff, I write what I did use on the reservoir so that the next person knows.
I'm just wondering what idiot put dexcool into a ford. Pretty sure only GM was stupid enough to use that stuff.

Compatible or not, I can definitely agree with not mixing coolant to be good practice. I won't mix oil or grease either.
 

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I know a lot of car guys and DIY guys who do their own maintenance to save money. I am in the camp where you either use the factory coolant or a known high quality coolant, but never ever mix the two.

In cars where I have switched to a different coolant, I flush...really flush the entire system including heater core. Thoroughly. I even drain it all and flush again with distilled water, then fill with coolant I have premixed, but usually not 50%, I look up the graph for the freezing temp and only run enough antifreeze to keep me safe down to 0F. I live in TX and in the summer you need all the help you can get in the summer, higher water % means better cooling.

Every person I have ever talked to who uses any random "universal" antifreeze ends up also being in the camp who either doesn't flush the system or flushes it half ass. They always end up with random cooling problems but most common is a leaking water pump. It usually isn't immediate, but like a few months or a year later. Despite all this, only one buddy of mine has switched camps and now agrees with me on this topic. I no longer try to convince any car guys of this because the universal antifreeze dudes never listen so I don't waste my words.
 
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