Here are the instructions for changing the PCV valve. The Subaru part number is 11810AA000 - ~$6.00.
If the valve is not too bad, you might be able to just clean it and get by.
- You will need a 19mm crow's foot or an end wrench that is slightly bent. See picture of JLittell’s special PCV Wrench at the end of the instructions.
- Remove the center cover on the intake manifold. It takes a 4mm allen wrench.
- Pull the hose off and remove the valve.
Note #1 - You are actually unscrewing the valve upside down. Set your ratchet as if you were trying to tighten something.
Note #2: - If you don’t want to drop the crow's foot under the manifold (it's a bear to get it out)
, secure the crow's foot to the extension using some electrical tape, or duct tape.
- Clean the old one or install a new one. It is possible to start threading it by reaching in from the driver's side, towards the back of the engine, under the manifold. It is a tight fit, but easier than trying to start it from the top.
- Pull the hose out and clean it while you have everything apart. The hose may be stiff enough that you can push it back on the valve by pushing on the other end of the hose, where it attaches to the splitter.
- Reassemble everything in the reverse order.
This is a custom PCV Wrench that JLittell had made. This has worked very well in loosening frozen or tight PCV valves that are very difficult to get out.