PCV valve installation question -- how far to screw in?

Where’d you buy it; is it the Toyota part?

There is a torque value. If I get a chance I’ll post a repair manual excerpt with the info. I believe the Toyota part comes with threads pre-coated with a Toyota spec thread-lock?

Anyway, as far as I know, something like Permatex Blue (with oil resistance) torqued to maybe 10~15 ft lbs, you should be ok.

Leaving it partially threaded in with anti-seize is not good.

If it’s not bottoming out (as you said) , is it the right one? Besides dimensional correctness, it needs to flow at the correct rate too.

 

PCV valves are going to be slightly different regarding thread length depending on who's making them as they're built to work on many different types of vehicles. The one I did had different threads than OEM and probably didn't even need to be replaced but I was doing the valve cover gasket so I wanted to make sure that it wasn't part of the reason the gasket failed. But in truth. I've not seen a truly failed PCV valve since the 1970's and that was barely even failed, just a super grimy leaky engine that never had oil changes much. Prius engines run so clean I can't imagine how a simple PCV valve would even fail.

 

Repair Manual (2nd gen) excerpt attached:

 

I'd be inclined to thoroughly clean and reinstall the OEM PCV valve, and order the Toyota part, through a dealership part department. It's under $10 USD I think. Even up here in CDN funds it's barely over $10.

 

Its much easier to actually remove the valve cover and do it. Seen many broken valve covers on this site as people use adj wrench instead of socket hard to get a socket in there. It does not have to be super tight anyway. With cover off you will see how close the valve is to the cover edge.
Plus likes of fun things to see under that cover. See my pic.

take the cops off the plugs and take pictures of the plugs in the well see if you see any oil in the bottom of the well thats from oil leaking past the valve cover gasket. Use your iPhone and take pictures of the well holes. It will look like my picture
Ive seen other 4 bangers that have a hardened seal on the gasket around the plug well this car does not just gasket material.

Also check the pvc hoses ends they may be cracked like mine see pictures. Track those 2 hoses back to the throttle body and pull them off the body and see how gunked that pcv hole is at the throttle body.
They will be clogged. Doesn't matter if the pcv valve is new if where the crankcase vapor is supposed to go is clogged.

You have that whole area opened up take advantage of it.

The throttle body is going to need a good cleaning especially if your using crappy engine oil.

Take pictures of everything in there your working on they come in handy later.

.

 

Do not "tighten it all the way". If you try to do that you will likely break the valve cover.
A normal bolt and nut use straight threads- the threads are the same width at all points. You tighten them by turning until the underside of the fastener makes contact and then you actually stretch the bolt slightly.

The PCV valve use tapered pipe threads. The threads at the end are slightly narrower and get wider towards the hex. So its conical in shape. As you install it the first few threads are loose- they fit closer together as you continue to screw it in and will become "tight" (wedges together) before you run out of visible threads. Continuing past this point will cause the valve threads to force the cover casting to spread apart until it cracks and splits.

Anti seize is a lubricant and can make it easier to over tighten things. Corrosion isn't a problem here so clean off all the antiseize, use a low grade thread locker (or pipe sealant) and tighten to factory spec.

Posted via the PriusChat mobile app.

 

Oh yeah: at least a couple of reports here, people tried to break the valve loose with an open ended box wrench, and levered a hole through the valve cover casting. Safest to pull off the hose first, use a deep socket, or a closed box wrench (with uniform radius at the working end).

 

Tough to get a socket wrench in there mendel there's alot of stuff blocking it.

The photo was after spending alot of time moving everything. But it can be done but at first glance looks easy for a box or adj wrench till you turn it real hard the first time and here CRACK...oohh that sounds expensive lol....

 

Hello, I replaced the PCV Valve on my 2007 2nd Generation Prius last night and assumed it needed to be tightened so that it was completely flush with the valve cover. It became so hard to go any further that I stopped and googled, and learned it doesn't need to be flush w/ the valve cover and could actually crack the cover if overtightened to that point. Fortunately no cracks, but my question is this: Should I leave the PCV valve as is (see photos), or should I unscrew it then screw it back in to proper torque specs of 20lbs, if I can even get torque wrench in there? (Unsure if leaving it this tight will cause cracking or other issues later due to engine heating and cooling.) Thanks!

P.S., the silver "goop" between the PCV Valve and the cover in this photo is just anti-seize.

 

Where you are, I’d back it out slightly, then, considering the anti-seize applied, torque but only to around 16 foot pounds.

 

Thank you, Mendel. Much appreciated.