[AltaBrig]

Does anyone know the required brake fluid for the Gen IV?

DOT 4?

Thanks.

 

[Jim_KT]

DOT3 or DOT4 according to the owner's manual.

 

[AltaBrig]

Guess it is the same as last Gen. Thanks.

Is anyone using the Valvoline Synthetic DOT 3 and 4?

Autozone site

 

[fun2drive]

Dot 4 Val. Synthetic in my BMW M3
Works just fine only difference between the two is the boiling point is higher for Dot 4...

 

[catric69]

Guess it is the same as last Gen. Thanks.

Is anyone using the Valvoline Synthetic DOT 3 and 4?

Autozone site

Yes, I flushed our old '10MY Outback with this very product. Also, my brother's '06MY Impreza with no problems what-so-ever. BTW all brake fluid is synthetic.

 

[lloyd123]

This note in the OB owner's manual puzzles me:

"Avoid mixing DOT 3 and DOT 4 brake fluids even if they are the same brand."

If DOT 3 is adequate then what harm could there be by adding a DOT 4?

Also, what comes from the factory? Seems the only "authorized" fluid that can be used to top off the reservoir would be what Subaru sells through the dealer's parts department.

 

[Scorched]

I have flushed the brake system with the valvoline synthetic fluid with no problems and have been running it for the last 5k or so without a problem.

Brake fluids are generally not advisable to mix because of boiling point differences in the fluids. If you mix a lower boiling point in with a higher one and for some (ungodly) reason manage to actually heat your fluid up that much you will boil the lower fluid while maintaining the upper fluid. And if anyone has seen boiling water and oil mixed together, this is a recipe for disaster. Also, different brands may use different additives/formulations to reach the listed boiling point, and may not be compatible.

My general take is that if you are going to work on the brakes, bleed the whole system through the drain plugs (having a helper man the pedal makes life a lot easier) and always refill with a single fluid type...whatever your choice may be.