Green coolant?

Mazda changed to the 55/45 mix a few years ago because of an issue with heater cores rusting
How does an aluminum heater core 'rust'? And even if it did, I can't see how reducing the water content from 50% to 45% would stop any corrosion. On a serious note, where did you come across this information.
 
Mazda changed to the 55/45 mix a few years ago because of an issue with heater cores rusting
Do you really thing Mazda heater cores have some unique, proprietary material that requires a 55/45 mix to prevent rust, a unique (or close to it) requirement in the industry? I don't. Maybe the problem is that Mazda branded FL22 is an inferior product that requires a higher coolant concentration.

By the way, what are the specs on Mazda branded FL22? No cheating by referencing something else that is purportedly compatible. I'd like to know what Mazda says in in the Mazda jug and I can't seem to find anything about it.
 
Yes, if the coolant looks milky, I definitely would do the same!

So the Ravenol FL-22 concentrate coolant you have looks "bright" green, does it look like the Prestone coolant we used in old days?

It's been a while since I've even seen the ole Prestone coolant. My truck and motorhome use Dexcool, my motorcycle uses blue Honda (in a Kawasaki) stuff, and the two Mazdas use FL22. But from what I can remember I believe the colors are close.

If I'm feeling really ambitious today (doubtful since it's ZERO degrees F in the garage) I'll snap a pic of the jug that I have of 55/45% FL22 sitting out there on the shelf.
 
Do you really thing Mazda heater cores have some unique, proprietary material that requires a 55/45 mix to prevent rust, a unique (or close to it) requirement in the industry? I don't. Maybe the problem is that Mazda branded FL22 is an inferior product that requires a higher coolant concentration.

By the way, what are the specs on Mazda branded FL22? No cheating by referencing something else that is purportedly compatible. I'd like to know what Mazda says in in the Mazda jug and I can't seem to find anything about it.

Again, see above on the state of my ambition. I'll snap a pic of the Ravenol concentrate (used in the MX) alongside of the OEM Mazda premix that I bought to top off the CX (the reservoir was low from the factory).
 
Oh, I seriously doubt they were rusting. Aluminum does not an cannot rust.

"To solve this concern, two mass production changes have been implemented.
a) The concentration of the coolant has been increased so that the amount of the contained anti-rust additive is higher.
b) The composition of the coolant has been changed (the ratio of the anti-rust additive has increased)"
 

"To solve this concern, two mass production changes have been implemented.
a) The concentration of the coolant has been increased so that the amount of the contained anti-rust additive is higher.
b) The composition of the coolant has been changed (the ratio of the anti-rust additive has increased)"
Thanks for posting that, now I know what's going on.

It's not the heater core that's rusting (because it's aluminum and therefore cannot rust), it's rust in the rest of the system that is getting caught up in the heater core and clogging it.

What happens with heat exchangers, which what a heater cores and radiator is, contaminants will concentrate in the exchanger, because of the swing in thermal properties from one side of the exchanger to the other.
 
My coolant was drained by dealer back in 1/2019 @ 47,018 miles when my crankshaft bearing seal was replaced under warranty

So the 120k mile interval got thrown out the window.

I did another roughly gallon drain and refill today. I just used some Zerex which was dark green like the stock fluid

81OyHpCq+YL._AC_SL1500_.jpg
81oPeZDLL7L._AC_SL1500_.jpg


I'm gonna do another drain and fill later this year.
 
One can't go on color alone. Look for the formulation.

That said, don't go adding blue to green or vice versa.

Read your owner's manual and follow the recommendations.
 
Like Conrad said, check the manual for the Mazda vehicle your changing fluid in as looks like you have a few Mazdas.

If it says FL22, only use Mazda FL22 or maybe the aftermarket ravenol FL22(may have to dilute the concentrated yourself)

I would use nothing else. My Mazda FL22 fresh from the bottle is a dark blueish green.

Although aluminum doesn't rust, it does corrode and pit very well. Whether it's my aluminum rims or my aluminum shelving that sat outside in rain/weather, aluminum corrodes and the corrosion flakes off possibly clogging coolant lines.
Aluminum corrodes alot slower than rust and may not be as visible but it does corrode. That's why the right mix coolant is important to your vehicle.
 
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Is it possible one can no longer go off the color? This Zerex was a dark green replacement that looked like this color.. same as what was in recovery bottle.


Not my picture
full-4894-25537-3af74bb9_fe64_47e7_b0a5_950da76e3064.jpeg
This is where things go wrong. That coolant is light green, the same color as my factory fill. Dark green would be British racing green or darker:
images
1966-Jaguar-XJ13-Le-Mans-18.jpg
 
It would appear then the dealer didn't replace with FL22 years back

This Zerex in picture was the same color as what was removed from vehicle



IMG_4892.jpg
 
My coolant was drained by dealer back in 1/2019 @ 47,018 miles when my crankshaft bearing seal was replaced under warranty

So the 120k mile interval got thrown out the window.

I did another roughly gallon drain and refill today. I just used some Zerex which was dark green like the stock fluid

81OyHpCq+YL._AC_SL1500_.jpg
81oPeZDLL7L._AC_SL1500_.jpg


I'm gonna do another drain and fill later this year.
Here's the back of my Mazda FL22 coolant jug....
 

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