Wonder if someone can help me identify this reservoir on a 2004 WRX STi, there are 2 reservoirs that sit next to each other on the left had side of the intercooler one small one larger. The one I'm not too sure about is the smaller one of the two that is right next to the intercooler. It would appear there is two brake fluid reservoirs as on the top of the cap of both reservoirs it states about using DOT 3 brake fluid. Have looked in the manual but doesn't appear to have my engine layout!. I think the reservoir maybe for clutch fluid?

I have some Halfords dot 4 universal brake and clutch fluid would this be fine to top up this small reservoir with, if infact this reservoir is for clutch fluid?

 

the smaller one is for the hydraulic clutch , yes dot 4 is fine to use
Cheers Ian