With the thousands of thoughts that flood our mind day in and day out we often forget the small things. The Pcv valve is an easily forgotten and rarely changed, but it is extremely important to keeping your Subaru running well.

A quick informative look on what a Pcv valve does for your engine, The three letters of Pcv stand for Positive crank case ventilation, when your engine is running there will be air, gases, etc that bypass the rings. If they aren’t able to vent it can cause the internal engine pressure to overcome the rings and push oil/oil vapor into the combustion chamber. This causes a less optimal burn which can foul plugs, ruin catalytic converters and ruin your mileage/power.

With all that said this is a very straightforward and easy repair that anyone with just a few tools can take care of. Let’s look at what tools, parts and know how will help us complete this install.

Time Frame

This is a very easy diy project that should take around ten minutes with the proper tools.

Tools

As with the simplicity comments above this will continue through with the few tools necessary to this repair. Your favorite ratchet, extension and 19mm socket will be everything you need. A flashlight can be helpful if are working in a dark area.

Grey Pneumatic 3/8th socket set

Gearwrench 3/8ths ratchet

Neiko extension set

The basic tools needed to complete this project

Parts

This is obviously a pretty easy answer as the titles states just in fact what we are replacing. The pcv valve, make sure that you find the vehicle specific part for your model. Fitments below

Subaru Pcv valve 11810AA131

2013-2017 Subaru BRZ

2013-2017 Subaru Crosstrek

2011-2018 Subaru Forester

2012-2016 Subaru Impreza 2.0L Non-Turbo

2013-2018 Subaru Legacy 2.5L-H4 Non-Turbo

2013-2018 Subaru Outback 2.5L-H4 Non-Turbo

Check your specific fitment but today’s vehicle utilizes this Pcv valve.

Installation

The Pcv valve is located under the hood, so we will go ahead and pull the latch and prop the hood up to assess our engine.

Next we will locate the throttle body and look just to the left of it from the front of the vehicle. There we will see a small black hose running from the intake manifold down towards the top of the block. Following this line down locate the Pcv valve.

Wide shot the hose and and surrounding parts.

This is the path way for air to travel between the engine and intake manifold. It isn’t held on by any clamps and comes off relativly easy

This hose should pull off by hand pretty easily, if you re having issues you can use a pair of pliers to break it free. With a light enough grip to move the hose, you can now twist the hose back and forth to break it free. Heat cycles with cause the rubber to becoming hardened and well formed to the pcv valve.

Pcv valve hose completely removed from both the Pcv connection and intake manifold.

Now you can see the Pcv valve, with your 19mm you can place the socket on the valve, attach the extension and ratchet and begin to remove it. Breaking it free can be difficult as many Pcv valves utilize a thread sealer/locker to keep them in place and leak free.

The new valve being fitted to the engine.

With the Pcv valve spun out you can give it a shake, if it rattles the valve was still working. A valve that doesn’t rattle indicates that it has been gummed up by oil vapors and was in need of replacement. With a pcv that is stuck and no longer rattles one of two things occurred, it was stuck shut over pressurizing the crank case or stuck open and which case the engine has the ability to suck in engine oil vapors all the time.

The empty hole in the engine where the Pcv valve calls home.

New and old. You can use a small amount of thread tape to properly seal the threaded section.

You may now start to hand thread the Pcv valve back in place. The threads it goes in are part of the block and something you don’t want to damage. Once it is unable to spin in further by hand you can take to your ratchet, once again taking care not to overtighten it and cause thread/block damage.

Completing that will bring you reinstalling the breather hose to intake manifold and you are basically done. Now is a good time to start the engine and make sure both ends of the hoses are well connected and leak free. A short slow ride around the block to further check your work should now be competed. Double check your connections under the hood after your drive and you are complete.

Pcv valve fitted to the block and hose properly engaged.

Congratulations! Your Pcv should now be working properly and getting engine pressures in check. You can now continue down the road for another 30k before the next valve is necessary.