[Tampa8]

Most of today's cooling systems use what the manual says, Ethalene Glycol based mixed coolant for aluminum engines, Such as Zerex Asian which is non silicate. This is a time where there isn't any advantage or requirement beyond the coolant saying it can be used in your newer car.
Hyundai for years has used MS-591-08 spec coolant so you could look for that on the label.

 

[Alex]

I just notice that the brake fluid on my 2022 SEL is a bit low. The owners manual says to use Dot 4. I went to pick some up at the store and all I see is Dot 4 synthetic. But I can't verify that the car uses synthetic brake fluid. So I'm unsure whether it is ok to add the synthetic or if I need to do a flush and replace. It only has 11,000 some miles so I was hoping to just add but wanted to make sure that either it's okay to mix, or that the factory uses synthetic.
Thanks in advance.

As long as the level is above the minimum line, you should do nothing. The way the brake system works is that as the brake pads wear, some of the fluid stays in the caliper. So the level at the reservoir will go down. You could add fluid, but if you do, when you replace worn pads and press in the pistons, the fluid could overflow the resrvoir making a mess. So it is best to not add.

As far as a fluid flush/replacement goes, it is usually not needed before 5 years of age. You can get tools to test how much water is in the system, but going by time is usually enough.

 

[garyahouse]

...As far as a fluid flush/replacement goes, it is usually not needed before 5 years of age...

Before we toss out too many opinions, let's just ask one question: What's the truth? Do I change my brake fluid when it gets dirty? Do I change it because it's hygroscopic and absorbs water? Well, yes and no. Problem is, we're missing the main issue. These things matter, but they pale in comparison to the primary reason. Closely related to WHY I should change my brake fluid is this question: How often should I change it? One guy says one thing, another guy says something else, and my mechanic says still another. Maybe a little more information from a credible source is in order here. Therefore I submit to the forum my version of ...

BRAKE FLUID 101
Forgive the technical nature of the following, but evidence isn't always one simple statement. If that's all we need, then take my word for it, change out your brake fluid every two years and you're good. If you want to know WHY I say that, then read on.
There's a lot I could say here, but let's focus on the most important issue and leave it at that.

Adapted from Brake and Front End magazine,
"The single most important reason brake fluid must be changed regularly is to replenish the anticorrosion additives. Corrosion inhibitors, pH stabilizers and antioxidants are added to brake fluid to improve the long-term corrosion protection of brake systems. Over time these corrosion inhibitors can become depleted leaving the internal parts of the brake system vulnerable to corrosion. There are many variables involved in determining how long it takes to deplete the corrosion inhibitors including brake fluid chemistry, chemical and thermal stability, brake system design, driving habits of the operator, frequency of maintenance, temperature, and road surfaces." I'm going to delete the rest of this quote just to prevent boredom, but here's the jist of it: "An extensive study found that the buffer capacity and inhibitor concentrations drop to less than 10% of their initial levels after only 30 months of service." Notice this quote didn't say they LOSE 10%. It said they only have 10% left, meaning they lose 90%. I'm not making this up, guys. "One of the studies found the rate of depletion is fastest at the wheels. This is where the fluid is exposed to the highest degree of heat. This heat causes the corrosion inhibitors to break down." Add to that new, unused, unopened brake fluid has a shelf life of 2 years. Don't ever reuse an open container, or an old one.
Want to read more for yourself? Fine: here ya go: CLICKY Enjoy.

But the bottom line is this:
Just change out your brake fluid every 2 years with fresh new stuff, and you're good.

 

[Alex]

Sorry, but the evidence would disagree. Maybe a little more information from credible sources is in order here. Therefore I submit to the forum my version of ...

BRAKE FLUID 101
Forgive the technical nature of the following, but evidence isn't always one simple statement. If that's all we need, then take my word for it, change out your brake fluid every two years and you're good. If you want to know WHY I say that, then read on.
There's a lot I could say here, but let's focus on the most important issue and leave it at that.

Adapted from Brake and Front End magazine,
"The single most important reason brake fluid must be changed regularly is to replenish the anticorrosion additives. Corrosion inhibitors, pH stabilizers and antioxidants are added to brake fluid to improve the long-term corrosion protection of brake systems. Over time these corrosion inhibitors can become depleted leaving the internal parts of the brake system vulnerable to corrosion. There are many variables involved in determining how long it takes to deplete the corrosion inhibitors including brake fluid chemistry, chemical and thermal stability, brake system design, driving habits of the operator, frequency of maintenance, temperature, and road surfaces." I'm going to delete the rest of this quote just to prevent boredom, but here's the jist of it: "An extensive study found that the buffer capacity and inhibitor concentrations "drop to less than 10% of their initial levels after only 30 months of service." Notice that it didn't say the LOSE 10%. It said they only have 10% left, meaning they lose 90%. I'm not making this up, guys. "One of the studies found the rate of depletion is fastest at the wheels. This is where the fluid is exposed to the highest degree of heat. This heat causes the corrosion inhibitors to break down." Add to that new, unused, unopened brake fluid has a shelf life of 2 years. Don't ever reuse an open container, or an old one.
Want to read more for yourself? Fine: here ya go: CLICKY Enjoy.

But the bottom line is this:
Just change out your brake fluid every 2 years with fresh new stuff, and you're good.

Interesting read. Everything I have read before points to the absorption of water by the brake fluid as the major cause of corrosion in the system. So checking the level of moisture in the system was a good way to gauge when to change your fluid. It also meant you would not get brake fade from a lower boiling point of brake fluid with a high water content. My prior car's, Honda Odyssey, maintenance schedule did not call for replacing the fluid every 2 years. It was longer, I believe it was 5 years. Prior to reading the information in your link I never hears of copper in the brake lines being a problem. I googled and read a bit more. It seems that copper in the system can cause ABS problems. You can buy test strips that will tell you when it is time to change your brake fluid. The strips are about a buck a piece. I might run out and get a few and use them to gauge when to change my fluid. From what I saw most car makers recommend longer than 2 years. Based on what I know now, I would use a copper test strip to determine when to replace the fluid. I any case, I would not go longer than 5 years. Even if the moisture level is low and the copper level is also low.

 

[garyahouse]

Something I'd forgotten:
Doing some additional research this morning, I was reminded of something I'd forgotten. I was wondering why brake fluid gets "dirty." Actually it turns from a very light tan to a deep amber color and worse. Needless to say, it's not DIRT. There is no dirt inside a sealed hydraulic system. However, the copper, which lines the inside of the brake lines, is the culprit. It leaches into the brake fluid over time. Reading the link I provided in post 23 above explains this.
It should be noted that what we call "dirty" brake fluid has nothing to do with water in the system. They are totally separate problems with different causes.

WE ALL NEED TO KNOW THIS:
Brake fluid contains corrosion inhibiters. They keep things clean inside the ABS system and the calipers. These inhibitors have a short lifespan: less than 2 years. From the article I linked above, "Another study found that the buffer capacity and inhibitor concentrations "drop to less than 10% of their initial levels after only 30 months of service". That's 2 1/2 years folks. Once these corrosion inhibitors fail, your braking system can begin to corrode because of accumulated copper and water inside the system: NOT good. This is why we're warned to flush the fluid every 2 years.
And as Paul Harvey used to say, NOW YOU KNOW THE REST OF THE STORY.

 

[garyahouse]

It's been awhile since we talked about this. But it's getting about time that those who bought '22 or '23 Tucsons think about this subject: it's time to flush the brake fluid, fellas. Check out this chart:

This chart gives you a frame of reference. Granted, our Tucsons use DOT 4, not DOT 3 as mentioned in the chart, but we have the same basic issue. Over time, brake fluid becomes contaminated with water. It's guaranteed. Most of us are pretty good at keeping up on oil changes. But let's not forget this important maintenance item. Truth is, we should be more concerned about getting STOPPED than we are about getting going...

 

[garyahouse]

AND REMEMBER; this new Tucson takes Dot4 LV class 6 brake fluid. The LV stands for low viscosity: it's thinner and flows better than regular DOT4. See Tamap8's post number 2 on this thread. Don't make the mistake of using anything else in the brake system.