What you need to know is if the Dot 4 in the Hyundai is Glycol or Silicon. They should not be put in together. Notice I didn't say mixed together because the don't mix.

Your manual tells you what to use, SAE J1704 DOT 4 LV FM VSS 116 DOT - 4 ISO 4925 Class 6
That must be on the label and it is Glycol.

Both btw are considered synthetic unlike motor oil that is mineral and synthetic and could be mixed if needed with no short term harm.

 

Thank you for the reply. I saw that in the owners manual but confused..
To clarify, is "SAE J1704 DOT 4 LV FM VSS 116" one option that must be listed on the product, and "DOT - 4 ISO 4925 Class 6" the second option that needs to be listed on the label? Or must the product have the complete "SAE J1704 DOT 4 LV FM VSS 116 DOT - 4 ISO 4925 Class 6" listed on the label?
TIA

 

Quite simply:
Dot 3: glycol based
Dot 4: glycol based
Dot 5: silicone based
Doat 5.1 glycol based

Dot 5 does not play well with others. It is silicone based, and cannot be mixed with ANY other brake fluid.

A great explanation is here: CLICKY
Interesting thing about brake fluid: it's hygroscopic. That means it likes water, just like a sponge. In fact, brake fluid is notorious for absorbing water. That's a huge part of why it fails and causes caliper and master cylinder failure. Most authorities recommend changing it out every 2 years or 30k miles. Warning: it's color is not an indicator of how much water it's absorbed. It doesn't need to be replaced because it changes color (that is: gets dirty). It. needs to be replaced because it absorbs water. They are two different things. Just so ya know...

 

Quite simply:
Dot 3: glycol based
Dot 4: glycol based
Dot 5: silicone based
Doat 5.1 glycol based

Dot 5 does not play well with others. It is silicone based, and cannot be mixed with ANY other brake fluid.

A great explanation is here: CLICKY
Interesting thing about brake fluid: it's hygroscopic. That means it likes water, just like a sponge. In fact, brake fluid is notorious for absorbing water. That's a huge part of why it fails and causes caliper and master cylinder failure. Most authorities recommend changing it out every 2 years or 30k miles. Warning: it's color is not an indicator of how much water it's absorbed. Just so ya know...

Good stuff, I always do a full brake flush on all my vehicles every 2 years, doesn't take long w/ a gravity MC filler tank and a willing wife lol Makes it easier (at least if your eyes are old) to use a white bucket, that fluid change in the clear bleed hose isn't as obvious w/ a dark bucket as a background

 

Almost forgot: to answer our OP's question, NO you don't flush and replace with something different than what came in the car. You replace it with the exact same stuff. Though flushing isn't necessary, it's certainly permissible if you like. However, even though all you need to do is replace, my question is why is your fluid low? Where did it go? You might want to try to track down the leak if indeed there is one. Is it possible that the car was low on fluid from day one? Yes, but doubtful. Most likely scenario is a leak. It is never normal to be low on brake fluid over time. It doesn't evaporate or burn up. Only possibility is a leak.

I've checked three sources, all agree that the Tucson takes xxxx fluid [EDIT: DELETED PER TAMPA'S POST #7 BELOW] However, I'm not convinced yet. Anybody else confirm?

 

Almost forgot: to answer our OP's question, NO you don't flush and replace with something different than what came in the car. You replace it with the exact same stuff. Though flushing isn't necessary, it's certainly permissible if you like. However, even though all you need to do is replace, my question is why is your fluid low? Where did it go? You might want to try to track down the leak if indeed there is one. Is it possible that the car was low on fluid from day one? Yes, but doubtful. Most likely scenario is a leak. It is never normal to be low on brake fluid over time. It doesn't evaporate or burn up. Only possibility is a leak.

I've checked three sources, all agree that the Tucson takes DOT3 fluid. However, I'm not convinced yet. Anybody else confirm?

100% not.
It's in my post, in the manual, DOT 4 along with the other requirements especially (ISO 4925) Class 6. Not all are Class 6, Ford I know in some applications also requires it be Class 6.
DOT 3 may boil in this application in fact without the additives in Class 6 it would be more prone to break down/ boil.

 

Post edited: thank you Tampa. Missed the post where it said DOT4 in the middle of all those letters and numbers you provided.

 

Hmmm, Guess I'll just be getting that ISO 4925 class 6 then for my Tucson when the time comes rather than getting the wrong DOT 4
It's a shame they've made the brake fluid classifications so convoluted over time

 

Agree having quite different versions of the same DOT number is not helpful.

 

Here's a pretty good read on class 6 (or Super DOT4)

Super DOT4 explained: ISO 4925 class 6 - Jaguar Forums - Jaguar Enthusiasts Forum

General Tech Help - Super DOT4 explained: ISO 4925 class 6 - Here is some information found while researching brake fluid, in particular the difference between ATE 200 and ATE SL6. This of course led down the rabbit hole as usual. It seems that the Super DOT4 appellation that has been flogged...

www.jaguarforums.com

 

So now that we figured out that we need DOT 4, Class 6 brake fluid, where can we buy it?
I think I found it here at Napa: CLICKY HERE.
and here at Walmart: CLICKY
Anybody know if there are other sources? I was searching for the numbers Tampa provided in post #2 above:

SAE J1704 DOT 4 LV FM VSS 116 DOT - 4 ISO 4925 Class 6

 

Glad this thread popped here. Seems there are several sources out there that are providing false info. You can always trust this forum...

 

Looks like Autozone has it on the shelf, at least at our local ones

https://www.autozone.com/brake-and-power-steering-fluid-additives/brake-fluid/p/liqui-moly-dot-4-brake-fluid-1-liter/1244554_0_0?spps.s=3404&cmpid=LIA:US:EN:AD:NL:1000000:PER:19488533498&&CATARGETID=120054150001289361&CADevice=c&gclid=Cj0KCQjwiIOmBhDjARIsAP6YhSW8pOsydTuWR9x6MfbrcheFTI9BGKaC1FDDID_WYhdd_L7_Pj-p0n4aAsLMEALw_wcB&gclsrc=aw.ds

 

0W20 synthetic oil, 1234YF freon, DOT 4/Class 6 brake fluid... seems like the prices of all the new breeds of fluids these cars require is becoming astronomical. Routine maintenance is sure getting expensive. We're paying 4 times what we did just a few years ago. Ha, don't even THINK about getting your air condoning recharged... THE STUFF IN OUR TUCSON IS BRUTALLY EXPENSIVE.

 

0W20 synthetic oil, 1234YF freon, DOT 4/Class 6 brake fluid... seems like the prices of all the new breeds of fluids these cars require is becoming astronomical. Routine maintenance is sure getting expensive. We're paying 4 times what we did just a few years ago. Don't even think about getting your air condoning recharged...

Getting crazy, I think the ATF for our Jeep Wrangler (ZF 8AT) if around $20/qt. Of course it's one of those BS "lifetime-fill" transmissions, which is no way should be a service-free transmission, but as long as it lasts until the factory warranty is up, I guess that's the lifetime that matters lol. Think my power steering fluid is like $25 a pint too

 

25 bucks a PINT???? Wow.
I think I can speak for all of us when I say I'm thankful for all the amazing technology they've packed into this Tucson, but it scares me thinking of what it might cost when some of this stuff starts to break. And it's no use fooling myself, keep it long enough and it WILL need some expensive repairs. Not tomorrow, thanks to an amazing warranty, but it's a bit scary thinking about it. 2023 has already proven to be a pivotal year financially. We're talking about the cost of fluids here, but consider car insurance, house insurance, groceries, gas, it's everywhere. I've always been one to enjoy the savings of owning an older used vehicle. I stepped out of character a good bit when I bought the Tucson this year. But hey, I'm. not complaining, it's an amazing piece of equipment. Hopefully, she'll prove reliable enough that I won't have to fuss with any big ticket items for a good long while.

 

Just a quick comment.....Often as your brake pads wear down, your fluid appears to be lower as well. This is due to the caliper moving the pad closer to the rotor as your brakes wear down.
If you can't find a leak, and you happen to add fluid to the reservoir to top it back up to the full level, then it will overflow when you get your brakes done in the future.
If it's just regular brake wear, when you have your brakes replaced, the fluid will then be at the full level.

 

Since we're talking about fluid specs, one thing that puzzles me is that there is no SAE/DOT/ASTM spec for anti-freeze that I've ever been able to find. The manual just says something about phosphate-based, ethylene glycol for aluminum engines. The yellow jug of green anti-freeze sitting in my garage just says guaranteed for all years/makes/models, can be used with any color anti-freeze. That seems overly generalized, especially since my car is 5 or 6 years newer than my anti-freeze. I assume that when I need a top-off, I can use my green stuff, but mixing it with the factory pink coolant, it sure will be an ugly color. 😀

 

Our Jeep requires a very specific coolant, it's got a pink hue and is supposed to NEVER be mixed w/ anything else, whether or not that's true, I don't think I'll gamble, especially since it's only about $18 for a concentrated (not 50:50 diluted) gallon jug. I won't be gambling w/ the new Tucson either, I know a lot of these universal fluids would probably get you down the road without issue, but if they do.................................................................................................

 

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.

 

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.

 

...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.

 

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.

 

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...

 

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.