DOT 3 vs DOT 4 Brake Fluid

[Varmint1967]

Which one is best for the Jeep Gladiator rubicon?

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[Minty JL]

Just use the OEM recommended fluid which is DOT3. It's a Jeep not a track rat

 

[Varmint1967]

No problem. I was only asking because DOT4 is usually recommended for heavier vehicles and the Gladiator comes in around 6,000 lb so I wasn't sure.

 

[NXTGENAutomotive]

Dot4 is a better fluid and is typically cross compatible. The one thing to keep in mind is that it is more hydroscopic and needs quicker change intervals vs Dot3.

All of our BMWs have used it for a long time and we always switch the Jeeps over. The factory recommended change interval on Dot4 is every 2 years regardless of mileage.

Get a LV (low viscosity) dot4 and you’ll notice a difference for sure.

 

[JTenn]

Which one is best for the Jeep Gladiator rubicon?

Simple answer is DOT 4 has a higher boiling point than DOT 3 but DOT 3 absorbs less water than DOT 4. I would run whatever is recommended which is DOT 3. The 2 are compatible but you should never put DOT 3 in a DOT 4 system because it can boil out in extreme heat situations. I would only mix them in an emergency situation to get me somewhere to properly repair the issue.

 

[Minty JL]

Just make life easy and use the OEM recommendation. Though I can play both sides of the field as an engineer.........just use what works. DOT3 is the OEM and rated for the limits of the vehicle.

The other dude talked about BMW and performance applications.......that doesn't apply here.

Just like the industry standards to fluid brake fluid is 2 years or 24k miles.......but how many people adhere to those standards. It all moot at the end of the day.

I use OEM brake fluid recommended and flush every 2 years or 25 months.

 

[NXTGENAutomotive]

Just make life easy and use the OEM recommendation. Though I can play both sides of the field as an engineer.........just use what works. DOT3 is the OEM and rated for the limits of the vehicle.

The other dude talked about BMW and performance applications.......that doesn't apply here.

Just like the industry standards to fluid brake fluid is 2 years or 24k miles.......but how many people adhere to those standards. It all moot at the end of the day.

I use OEM brake fluid recommended and flush every 2 years or 25 months.

Not totally true. It all comes down to the use. The most basic bmw 228i gran coupe that is mostly a service loaner and is technically a mini cooper has the same dot4 fluid from the factory as our M4 competition that is running almost 750 hp.

We don’t track that M4, so we leave the OEM fluid in it, but if it was going to the track, it would get upgraded.

If you tow, if you wheel hard, if you haul heavy weight, there are definite scientific benefits to running the dot4 low viscosity fluid in the Jeep. If it’s mostly a dd or a mall crawler, doesn’t make a difference which fluid.

it definitely does not need to be a race car to run Dot4. Plenty of uses where it is beneficial on our Jeeps. Given how much we are always working on our vehicles, I have no problem changing the fluid every two years personally. If nothing else, it for sure makes a difference towing

 

[Sweetums]

Just use the OEM recommended fluid which is DOT3. It's a Jeep not a track rat

F@ck it, use nothing but Castrol SRF, an absolute bargain at $80 per liter. I have to use this stuff in the motorcycle because it has a habit of cooking the rear brake fluid with the exhaust heat. Since it uses a thimble-full, I use the vacuum sealer from the kitchen to reseal the bottle.

 

[Lost1wing]

Not totally true. It all comes down to the use. The most basic bmw 228i gran coupe that is mostly a service loaner and is technically a mini cooper has the same dot4 fluid from the factory as our M4 competition that is running almost 750 hp.

We don’t track that M4, so we leave the OEM fluid in it, but if it was going to the track, it would get upgraded.

If you tow, if you wheel hard, if you haul heavy weight, there are definite scientific benefits to running the dot4 low viscosity fluid in the Jeep. If it’s mostly a dd or a mall crawler, doesn’t make a difference which fluid.

it definitely does not need to be a race car to run Dot4. Plenty of uses where it is beneficial on our Jeeps. Given how much we are always working on our vehicles, I have no problem changing the fluid every two years personally. If nothing else, it for sure makes a difference towing

Dot 4 is more hydroscopic than dot 3. Good thing our Jeeps never see water! That being said, our Jeeps will never generate the heat as vehicles on the track. As a daily driver, Dot 4 will work but not needed.

OP, stick with Dot 3. You will not benefit or feel a difference.

 

[SimonH]

I would always go DOT4, here in Europe there is Dot3 hardly available, as its low boiling point.
Dot5 or even 6 is more for track cars, where brakes get really hot.

For Gladiator standard DOT4 will suit no problem.
end of day DOT3 will work as well, as its factory in US Gladiators.

 

[JTdiRtyD]

Mostly flat land driving. Little to no towing or off-roading. - DOT3 with factory recommended changes

Frequent mountain driving, towing, or off-roading. - DOT4 with more frequent changes.

 

[arosen1997]

Dot5 or even 6 is more for track cars, where brakes get really hot.

As far as I'm aware, DOT 5 and DOT 6 also don't work with ABS systems.

 

[SimonH]

As far as I'm aware, DOT 5 and DOT 6 also don't work with ABS systems.

That‘s not correct. It worked in my Corvette and M3 flawless (DOT5.1)
It simply has higher boiling point, but need to be changed more often(once per year due to watering)

 

[arosen1997]

That‘s not correct. It worked in my Corvette and M3 flawless (DOT5.1)
It simply has higher boiling point, but need to be changed more often(once per year due to watering)

Well you are partially correct, however DOT5.1 is glycol based, OK for ABS systems. DOT 5 is silicone based, not OK for ABS systems as it actually dissolves air into the oil which is released upon rapid agitation (like when the ABS module engages) effectively creating air bubbles in your system. Alternatively though, silicone based DOT 5 is hydrophobic which would have nice benefits for offroading. I was wrong about DOT 6 though, that's fully backwards compatable.

 

[Hootbro]

DOT 3 and if in a pinch, DOT 4 is an allowed alternate.

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