DIY: PCV valve replacement (pictures!)

**WRXreX** · 04-21-2007 07:49 PM

Spent 30 min replacing PCV valve on my 2002 WRX today.

Tools you need:

3/4" wrench
12mm socket & wrench
PCV valve from autozone: PN PCV1142

First, you have to remove TMIC and it can be done by following steps I posted here:

http://forums.nasioc.com/forums/showthread.php?t=964852

Once TMIC is removed, please follow these 'simple' steps:

Disconnect blow off valve recirculation pipe from BOV and pull it away so that you can reach PCV easier.

Disconnect this hose (small amount of coolant may spill out)

PCV is located here:

Simply pull the hose away to expose PCV:

Using 3/4" wrench, remove PCV:

**WRXreX** · 04-21-2007 07:50 PM

New PCV vs old PCV (35k miles)

Old PCV

**WRXreX** · 04-21-2007 07:51 PM

Do everything in reverse order and you are all set! Enjoy your new PCV valve!

**rr1911** · 04-24-2007 02:47 AM

great write up

**PolarisSnT** · 05-29-2007 09:17 PM

You should note that the 2004s are different than the 2002/2003s. The PCV isnt in the manifold, it is housed in a plastic elbow right off the crank case.

**tarmacsti** · 03-09-2008 11:42 PM

If I may ask... what is the purpose of changing this valve?

**rr1911** · 03-10-2008 02:40 AM

Originally Posted by tarmacsti

If I may ask... what is the purpose of changing this valve?

to keep oil out of the intake track

**tarmacsti** · 03-10-2008 03:02 AM

How would I know if I have to replace this?

**rr1911** · 03-10-2008 03:14 AM

its reccomended to change it every 30,000 miles

on some of my family members cars i use to change it every other time i did an oil change for them.. the subie one is kinda hard to get to

**ODJ** · 03-10-2008 05:05 AM

Originally Posted by PolarisSnT

You should note that the 2004s are different than the 2002/2003s. The PCV isnt in the manifold, it is housed in a plastic elbow right off the crank case.

My understanding from a previous PCV thread was that 2004 models have a PCV setup that's meant to be non-serviceable. Has anyone done the replacement in an '04? Anyone have a definitive opinion on whether or not this operation needs to be done with an '04 at all?

Edit: it's this thread here, which has gotten stickied at some point.

**lytlec** · 10-01-2009 08:35 AM

Does anyone know if this is the same for an 06 WRX?

**05AspenWhite** · 12-15-2009 11:00 PM

Don't know if there are any major differences between the 05 or the 06 STi but here is a very helpful link. I spent about an hour looking for this write up and I hope it helps someone. I am changing my PCV valve tomorrow if, and I do pray, a local auto parts store has one.

I don't have a Subaru Dealer near me for miles. Anyways, people will say that changing the PCV valve is non-essential according to the manufacturer, but they are likely basing there calculations on a car that is bone stock. Any Joe Schmoe knows that when you add aftermarket parts to your car, it changes a lot of things, and that's to include the risk of clogging the PCV valve and overpressurizing the crankcase. I think I have said enough.

How To: Replacing pcv valve - IWSTI.com: Subaru WRX STI Forums

**05AspenWhite** · 12-16-2009 04:52 AM

Originally Posted by tarmacsti

How would I know if I have to replace this?

I will second what rr1911 said in that replacing the PCV valve keeps oil out of the intake track

. In extreme cases, a clogged PCV valve can cause oil to push past the piston rings into the combustion chamber and that is not fun for anyone. I guess some signs are oil sodden spark plugs, misfiring, or CEL with blinking cruise control light (caused by misfiring). You just really have to pay close attention when performing maintenance on your car.