I compiled this with a little searching:
What does Mazda say about FL22?
To enhance service life, reduce waste material, and lower maintenance costs, a new long-life pre-mixed “FL22”
engine coolant is recommended for your Mazda3.
It is recommended that FL22 coolant continue to be used for models originally filled with FL22 coolant from the
CAUTION: FL22 coolant is “pre-mixed” and must be added to the cooling system as is. DO NOT ADD
WATER TO FL22 COOLANT. Adding water will dilute the solution and lessen the effectiveness of
If coolant replacement becomes necessary for prior Mazda models (not originally filled with FL22 coolant), FL22
coolant can be used. If FL22 coolant is used for prior models, be sure to place the FL22 sticker on the reserve
tank or degas bottle to indicate FL22 coolant is being used.
• In the case of prior models, the coolant replacement interval is every five (5) years or 60,000 miles
• Six (6) FL22 stickers are included with each case of coolant.
What does FL22 say on the bottle?
Ethylene glycol based
55/45 mixture recommended
Developed to provide corrosion and rust protection
Boiling point 270 degrees
Freezing point -47 degrees
Ethylene Glycol (107-21-1)
Diethylene Glycol (111-46-6)
Potassium Hydroxide (1310-58-3)
Proprietary Inhibitors (NJTSRN 217).
"DO NOT USE coolants containing: Alcohol, methanol, borate, or silicates"
What does the manual say about coolant replacement?
FL22 120,000miles or 10 years
Others 60,000miles or 4 years
Who really makes FL22?
Old World Industries (the makers of Peak, Sierra, and other antifreeze brands) state that FL-22 is a Motorcraft extended life coolant and that either Peak Global Lifetime or Peak LongLife Antifreeze can be added to FL-22 without issue. Both of those are silicate free, and LongLife is also phosphate free.
What coolant do I need for my Mazda3?
Any modern coolant that is silicate/phosphate free which is a majority of the green coolants on the market. When you view the ingredients of FL22, there's nothing special. Just make sure you do not exceed 60% antifreeze as a part of your solution. (Per the service manual)
How much coolant do I need if I drain the radiator and fill it up myself?
About 1 Gallon of premix, or half gallon of antifreeze + half gallon of distilled water (If you mix your own).
What will my FL22 coolant probably look like after 30K miles?
Why not go to the dealer for a flush, How much will it cost?
If you get your car’s cooling system flushed at a dealer or mechanic, they will flush all
of the coolant. My Irvine Mazda dealer quoted $110, but that was with a coupon. So it could be higher or lower depending on your dealer. I believe this dealer flush should be done before 60k miles. I might get mine done at 40k miles... Now Mazda may state to change the coolant at 100k miles or the coolant may be a special long life formula, but I'd feel much safer changing the coolant every 2 years or so. The main reason is because of the metals in the cooling system that "erode" into the coolant. (Erosion, Electrolysis, corrosion, rust, etc).
I decided to use ZEREX by Valvoline G-05 coolant – (A Ford and Chrysler coolant). The color of this coolant is still green, though a lighter almost yellowish green color. Since this coolant appears to be compatible with FL22 (Just like Peak Global Extended Life), I decided to buy it for like $11. You can pay extra for those extended life coolants, though I would still want to flush the coolant every 2 years or so. It's a small price to pay compared to fixing damages done by erosion and corrosion.
Is there a DIY coolant flush walk through?
Here’s how I did the drain and refill (keep in mind, this should be in the factory shop manual, but I did not find it in the user manual)
Take off black plastic skid plate that you normally remove when doing an oil change.
Make sure the engine is COOL so the radiator is not under high pressure.
Unscrew the cap from the pressurized plastic coolant reservoir on the left side of the engine bay. If the engine is still slightly warm, you might hear a “hiss” of pressurized gas escape. Unscrewing this cap allows “air” into the system for coolant to drain at the drain plug.
Locate the black plastic drain plug on the bottom of the radiator, and unscrew it using a short wide flathead screw driver (Or short, wide head Phillips screw driver). Try not to strip the threads of the plastic drain plug.
Once it’s unscrewed, there’s still a portion of the drain plug preventing fluid from draining, You have to pry at the plug a little and pull it straight out enough so that the fluid drains.
Cold or warm coolant should then be coming out of the radiator drain plug. Catch this in a container that can hold more than a gallon.
As the coolant drains you will see your coolant reservoir level drop (Located on the left upper area of the engine bay). This is where you fill re-fill your car with new coolant. (Do not confuse windshield washer fluid for coolant)
Once coolant is drained, retighten drain plug snug by hand (firm, don’t over tighten or strip the plastic head)
I used a 50/50 distilled water to anti-freeze ratio.
Total coolant drained was exactly 36,900 ml in my car. Or 3.7 liters (0.98 gallons) This may vary depending on how full your reservoir is at the time you drain your coolant. I know I didn’t let ALL of the coolant drain from the radiator, though I did let a majority of the coolant drain.
What I did next was then fill up one 0.5L (1 pint) water bottle with distilled water, and another bottle with coolant. Then I poured these into the reservoir. I repeated this process until it was about a gallon (same amount of coolant removed).
For disposal, depending on local laws, you might be able to dump it in your sanitary sewer system (toilet), or you may have to take it to a nearby hazardous waste collection facility. (1-800-cleanup). Just don’t dump it into the gutter.
For replacing MORE coolant, simply repeat the process after making sure coolant has cycled throughout the engine (Enging reached operating temperature by driving it around for like 5 minutes/etc).
DISCLAIMER - I take no responsibility if you forget something, there's a coolant leak, and you blow an engine etc... Work on your car at your own risk.