Looking to purchase brake fluid to keep at home. I've recently learned here that the clutch system shares the same fluid. Do I purchase OEM or is there a better brand recommended. Something that can be safely added to the existing fluid should the need ever arise. Or is mixing not recommended? Thank you.

 

See Google. Brake fluid is hygroscopic, it absorbs water vapor. Under sever use the water vapor will boil and brakes fail. You can buy an inexpensive brake fluid tester from Amazon. 2% is a rule of thumb to change. Most manufacturers recommend changing every 2 years while some have started testing to determine need.

 

OEM is just fine for pure street use. If you're taking the car to the track look at Endless or Castrol SRF.

 

I used pentosin super dot 4 in my 2009 manual.

 

Can the pentosin be mixed with OEM should I need to add any?

 

ATE Type 200 has been a good choice for me.
Any DOT 4 fluid should be fine for street use.
If you change it every other year, you'll be set.
As noted, you can buy a moisture meter on Amazon
to see if you really need to do a flush at the two year mark.

 

+1 on the Pentosin

 

I use Motul RBF600 in all my cars, not because they all get raced, but because if you've ever had a caliper piston get stuck and drag on the rotor where it got so hot it boiled the brake fluid in the system and you had hardly any brakes when you tried to stop, you'd want to avoid that happening ever again so the extra temperature threshold it supoorts is nice insurance and peace of mind.

 

Pentosin.

 

yes