DOT3 or DOT 4 Brake Fluid ?

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My 2017 Sonata needs new brake pads - was thinking of doing a brake fluid drain and fill as well to remove built up moisture : Which specification do you find best for late model vehicles - DOT 3 or DOT 4 ?
 
I use DOT4 in all of my vehicles, it is very easy to find. It can stand a bit more heat, and is a little less prone to water absorption. Having said that either will be fine.
 
I'd put in it whatever it calls for. If it calls for DOT3, I'd put DOT3 in it and not worry about it one bit.

One thing you technically shouldn't do is put DOT3 into a vehicle that calls for DOT4 - it lowers the boiling point - now would I worry about that in a pinch? Nope.
 
I'm turning this to a teachable moment for those who have such a vehicle as many are unaware of it.

There are actually two different DOT 4 brakes fluids. Ford as an example has been specifying DOT 4 LV in many models for a few years. LV means low viscosity. Other auto makers such as VW and Audi also specify DOT 4 LV brake fluid.
Newer F150's spec DOT 4 LV.

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I have the LV fluid in my truck, Bled it in with the last brake job. Seems to work well, a bit more responsive.
 
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Valvoline Brake fluid can be found cheaply and meets Dot4 spec. Best bang for the buck in brake fluid IMO.
 
Originally Posted by Jimzz
Valvoline Brake fluid can be found cheaply and meets Dot4 spec. Best bang for the buck in brake fluid IMO.


^This. $6 a quart on sale at Advance. Picking up a case today.
 
Here is a little write-up from Pentosin to supplement the LV comments in this thread. Note Rockauto sell 5 Liter of Pentosin for $34, Amazon wants $51 for the same container.

DOT4-LV; 5 Liters
Pentosin DOT 4LV is a special brake fluid of highest DOT 4 performance levels and extremely low viscosity at cold temperatures. It offers safety against vapor Lock; it has excellent resistance to absorbing and retaining water and provides superior corrosion resistance. Pentosin DOT Lv Brake Fluid is ideal for all modern vehicles with ESP and ABS. DOT 4 LV can be used in all vehicles that require DOT 3 or DOT 4 fluid.
 
Use dot4!

Dot4....for "old" cars with ABS systems...

Dot4LV...for cars with more refined ABS (TCS, ASR,...) systems which are quicker/more refined...
 
I simply follow the owner's manual, which for me has always been DOT 3. No mountains here nor spirited driving. While demarpaint states that it is slightly less prone to water absorption, my understanding (correct me) is that when it does absorb water, the boiling point drops off faster/more compared to DOT 3. It always seems that DOT 4 recommends more frequent changing (again, correct me if wrong).

I'm not convinced that DOT 4 is better in applications that don't recommend it. On the other hand, I use Fram Ultra Guard filters for only one OCI, so don't believe any of my opinions, LOL.

https://www.apcautotech.com/getmedi...ic-White-Paper-D5-Brake-Fluid-Basics.pdf

"A seldom talked about characteristic is that because of this chemistry, the DOT 4 fluid will have a more stable and higher boiling point during the early portion of its life, but ironically once the fluid does actually begin to absorb water its boiling point will typically fall off more rapidly than a typical DOT 3. ... The real differentiating factor is that DOT 4 fluid should be changed more often than a DOT 3 fluid, because of the effects and rates of water absorption."
 
Originally Posted by demarpaint
I use DOT4 in all of my vehicles, it is very easy to find. It can stand a bit more heat, and is a little less prone to water absorption. Having said that either will be fine.

I'm pretty sure dot4 is more prone to water absorption
 
Originally Posted by skyactiv
I'm turning this to a teachable moment for those who have such a vehicle as many are unaware of it.

There are actually two different DOT 4 brakes fluids. Ford as an example has been specifying DOT 4 LV in many models for a few years. LV means low viscosity. Other auto makers such as VW and Audi also specify DOT 4 LV brake fluid.
Newer F150's spec DOT 4 LV.

Pentosin says that DOT4 LV is backwards-compatible with regular DOT4 too. I have Pentosin for my wife's Fusion (which specs DOT4 LV) and plan to use it in our other cars. It supposedly provides a better "feel" as well.
 
Originally Posted by Jimzz
Valvoline Brake fluid can be found cheaply and meets Dot4 spec. Best bang for the buck in brake fluid IMO.

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I grab it when they run it on sale, it is a best bang for the buck fluid.
 
It WAS the best bang for the buck. I just saw Supertech Dot 4 brake fluid at Walmart. It's $5.74 for a quart and the Valvoline is $5.99.

Can't find a spec sheet for it so hard to say exactly how good it is.
 
I've grabbed it on BOGO sales, which made it the best bang for the buck for me. They run those deals on occasion at AAP, otherwise yes the WMT deal is better.
 
Originally Posted by Wolf359
Can't find a spec sheet for it so hard to say exactly how good it is.

If I'm not mistaken, DOT4 is the spec so it either meets it or it doesn't. There's no "how good it is" at play.
 
It's a minimum spec. Some DOT 4 fluids like Pentosin exceed minimum DOT 4 boiling point specs. Walmart doesn't really list it on their website, but it might be on the bottle somewhere and it's probably the basic DOT 4 minimum.
 
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