PCV Check Valve
 

Hey all, as some of you have probably read in other posts of mine, it looks like my PCV check valve needs either cleaning or replacing. I was wondering if there's a how-to (i couldn't find one) or a walkthrough on how to stop my oil dipstick from popping up due to the pressure build up.
On a scale of 1 to 10... 10 being hardest, does anyone know how hard it is for someone like me to fix? (I don't have too much equipment and experience). If i were to see step by step pictures and instructions, I'd like give it a good shot.
Thanks, Jordan.

How-to Documents link at the top of the page
 

Really helpful.

http://www.subaru-svx.net/photos/user.php?How-To|14272

I would replace the o-ring on the dipstick as well. It is usually very brittle by now and when you push the dipstick down, it just slides in and doesn't snap. When you replace it, it will take more pressure to put it in, but it won't work it's way out either. Good luck. :)

yeah that's an awesome how to, thanks a lot. My last question before i rip into it. Is this part specific to any other Subarus? or just to the SVX... That way I'll know whether the part is already in Australia or not. If it's SVX specific then I obviously won't fix it today, because i might need a new check valve, but if other Subarus have the same part then that's be great

It's the same on every Subaru I've ever owned.

I think some of the newer (2005+) may be different???

Hey, I hate to sound dumb, but what's the functionality of the check valve?? and also, is the I.R.I.S valve a whole different ball game?
Jordan.

It is in no way dumb to ask questions about things you have not learned or things you have not experienced.

It is smart.

I'm no engineer, so I'll give you a layman's interpretation. ;)

The Positive Crankcase Ventilation [PCV] system is designed to let blow-back gases from the lower part of the engine back into the intake in order to burn them in the engine, rather than vent them to atmosphere.

There is a series of pipes connecting the heads and the crankcase to achieve this. Under part throttle there is a vacuum in these pipes which helps divert the blow-back gases to the intake. Under hard throttle there is no vacuum. The PCV valve reacts to this and allows crankcase gas to the manifold under these conditions.

If the PCV valve is broken or stuck, the crankcase will pressurise.

The IRIS valve is a whole new ball-game and a different kettle of fish. :D
The IRIS valve is electrically controlled by the engine computer. When driving at slow revs it changes the length of the inlet tract in order to provide higher torque in the engine. It closes once the revs are higher and the gas velocity is at a high enough level. It has nothing at all to do with emissions control, which is what the PCV system is all about. Its primary function is to vary the intake tract to maximise torque.

You could think about the IRIS as the reverse or opposite of a Vtec system. Vtecs as we know them vary the outlet valve opening to maximise torque low down, and open up to increase hp higher up the rev range. Well the IRIS does a similar job, except it does it by varying the speed of the gas at the inlet side, rather than at the exhaust side.

I hope this helps.

Joe :)

You are just full of it Joe!
 

A world of great much needed information!
A day without learning, for me , is like a day without sunshine.
You are appreciated much!
Thanks for being there for us.
Keith

AWESOME, thanks a lot, really helps when you know what your looking at and now i do!

My next issue is that i dont have a crow's foot or oxy torch to bend a wrench, any ideas? Has anyone done this another way?

Jordan.

You are welcome guys, I'm learning as I go along myself.

Jordan, the only other way I can imagine is to remove the intake, then it's easy.

However, don't tackle this without a WSM, because there is a jumble of vacuum pipes and tubes and some electrical connections under there. You are sure to break or damage some if you don't disassemble in the proper sequence.

Beg borrow or steal a crow's foot is my advice. Jobs are always easier with the right equipment.

Joe :)

no way am i taking off the intake, too much effort, im lazy!
im getting a tool shop to order in a 19mm crows foot for me, then im gonna use it once and then it will soak up dust in the garage for the next couple of years and then it will mysteriously disappear like the rest of my tools :lol:

Re: PCV Check Valve
 

Hey dere. Where and what is this dipstick to which you refer with respect to the o-ring you mention? Thank you.

~Robert

Re: PCV Check Valve
 

Check out my locker, I made a custom tool to remove the PCV valve. Try making one up, it really made the job easier for me.

Re: PCV Check Valve
 

I don't know what size pcv valve they use down under but 19 mm is a bit large here in the states. I think it's either 12 or 14mm.It's been awhile since I did mine so I forget exactly.I also just used an open end wrench but I guess a crowfoot would be a bit easier.Good luck

Re: PCV Check Valve
 

It's 19mm here too...

<trying to picture how you got an open end wrench in there???>