2018 Subaru Outback: DOT 3 or 4?

[Marc Hufnagel]

Going to do a brake fluid flush on my 2018 Outback. I am trying to determine if I have 3 or 4 in there from the factory. The manual says 3 or 4. Whatever is in there I'd prefer to stay with - thoughts? Also as a side question; anyone ever bled the ABS module on a late model Subaru?

 

[Rand]

if you dont let the reservoir get too low and suck air in you should be ok.
3 and 4 are very similar. I'd recommend using 4 if they are the same price and availability.

 

[MRC01]

Going to do a brake fluid flush on my 2018 Outback. I am trying to determine if I have 3 or 4 in there from the factory. The manual says 3 or 4. Whatever is in there I'd prefer to stay with - thoughts? Also as a side question; anyone ever bled the ABS module on a late model Subaru?

When I bleed my wife's 2018 Forester, I use DOT 4. I don't give the ABS module any special attention. I start by using a big turkey baster to suck the old fluid out of the reservoir so it's nearly empty. Then fill it with fresh fluid. Then bleed at each wheel, starting with the furthest away (R side rear) working toward the closest wheel. At each wheel, repeat the cycle (valve closed, brake pedal push, valve slowly open, pedal to the floor, valve closed again, brake pedal slowly up again) until fresh fluid comes out. Then replenish fluid at the reservoir to replace what bled out. Then move on to the next closest wheel and repeat.

 

[TumblrDucks]

Could also consider ATE type 200 or Bosch ESI 6, superior standard than DOT3/4.

 

[doitmyself]

I did a bit of Googling and get the impression that most Subie's come with DOT 3?

This 2018 service bulletin shows DOT 3: https://www.google.com/url?sa=i&url=https://www.subaruforester.org/attachments/06-62-18-pdf.524191/&psig=AOvVaw1yVdZM4adAelAo7PlqrWHI&ust=1645668009657000&source=images&cd=vfe&ved=0CAkQjhxqFwoTCOipxpvdlPYCFQAAAAAdAAAAABAk

The few sites I visited suggest that the brake reservoir cap states DOT 3. Check yours.

The majority of Subaru brand brake fluid images show DOT 3 (I did find one ebay pic of Subaru DOT4)

I would take a peek at your brake reservoir cap and follow that. Pic below is from Subaru parts dealer:

 

[MRC01]

I did a bit of Googling and get the impression that most Subie's come with DOT 3?
...
The few sites I visited suggest that the brake reservoir cap states DOT 3. Check yours.
...

On my wife's 2018 Forester, the brake fluid cap says DOT3, while the manual says DOT3 or DOT4. DOT3 tends to absorb moisture slower, while DOT4 has a higher boiling point. My guess is that Subaru recommends DOT3 because they assume most people don't maintain their cars properly. DOT3 and DOT4 are miscible, so it doesn't really matter.

 

[The Critic]

DOT3.

Prestone® MAX DOT 3 Brake Fluid - Prestone® Total Protection

Prestone® MAX DOT 3 Motor Vehicle Brake Fluid is our highest-grade formula, maximizing performance vs. DOT standard. Prestone MAX is our best brake fluid at preventing overheating and brake fade.

prestone.com

Boiling point is higher than most DOT3 fluids. Available at AAP or Autozone.

 

[Pelican]

Either is good, the difference is that #3 is less hygroscopic, but reaches boiling point faster than #4.

 

[doitmyself]

The DOT 3 vs. DOT 4 discussions get beaten to death. I think that some people have a biased opinion that DOT 4 is always "better" (maybe because of the higher number,LOL?). They both work. They both have pros/cons. Choose the one based on your bias. Some choose DOT 4 because the think they need a higher boiling point. I choose DOT 3 because that's what came OEM in my ride AND I think DOT 3 manages moisture better (my bias). I live in the flat lands and have never put my brakes into a high stress situation.

To ease the OP's decision, I recommend that he follows what's on his reservoir cap (DOT 3). That's probably the OEM fluid. The manual says you can use either. I'm just trying to ease the OP's decision making process, but he did not share with us what his driving conditions and style are. So, around and around we go!

 

[dubber09]

I switched to Bosch ESI6-32N awhile back and keep using it, good with ABS as well.