PCV valve replacement in 351 EFI ... what I learned
 

Where is it? I don't think mine has a PCV valve? Answers.

Yes, on my 94 5.8 you can pull it out of the valve cover, passenger side toward the rear. Push down on the hose behind the engine while working it out of the grommet. Then you can struggle to pull it out of the hose and give up. That is good because that is just an ell, not the PCV valve.

Wait, let me back up.. to reach it remove the jack crank because your knees will not like it there. Get a ladder, etc. to get your knees on the radiator support. Put your right hand on the back of the engine, left about to be very oily, to pull out the PCV...you think.

The PCV hose runs around the back of the engine up front to between the throttle body and the vacuum tree in the upper intake manifold. Fish it out and you will find the following: Ell that went into the valve cover, An "L" shaped hose and the PCV valve is clamped into the other end. From the PCV there is another hose to the intake. The replacement "F" shaped fitting on the PVC is no issue because iit does not squeeze in between the valve cover and upper intake. The PCV valve is sitting on the top of a hose end.

I guessed mine had never been changed and was surprised to find it fairly clean at 190,000 miles. The old one had a PV68A number and made in USA. I find that Purolator number fits a 1979 Bronco, not sure about later years (mine is 1994) so it had been replaced by someone for the previous owner. I bought Motorcraft this time.

But wait! There is more, be sure you break the thin yellow vacuum hose going to the thingamajigger on the back of the engine. I had some hose to patch with but braille is not my forte. Bottom line.. success.

So the PCV valve manufacturers want you to replace often, others say clean with carb cleaner, other say test and don't replace unless necessary. I found the wrong one installed in mine. It is your choice. Just be ready to break a thin vacuum line in the process. However, the project is not as difficult at it seems.

I changed mine some years ago, haven't bothered to look at it again... i just got a little dirty, but it was fairly easy.

Forgive me while I chuckle... PCV valve replacement = RPITA on EFI 5.0 and 5.8 truck engines! Finding it is just the beginning of the excitement. The FAQ's at the top of this forum list the location if anyone forgets how to find this thread again.

Royal pain is correct. Ford had a great idea getting the PCV valve up out of the oil several inches above the valve cover and mounting it vertically for better operation. I have no idea if I got mine vertical again and don't care at this point. I do know it has been replaced and with the correct part.

PCV valve in 1994 5.8 351
 

Here is a picture to go with my story. I'm wondering if one could just loosen the hose clamp on the PCV valve and make replacement easier?

This is my first attemp at a picture here.
Note my thumb is on the PCV valve. Only an ell goes in the valve cover. Well, that picture upload did not work. Nor did the one to my CP. Guess I need picture help.

Well, I'm trying again to show PCV picture. The new PCV valve with the caped "'F" shaped connection is at my thumb. Ell that goes into the valve cover is at the bottom.

Attachment 23335

After a couple of days to get semi-clean it occurred to me that one MIGHT use a nut driver (5/16) to loosen the clamped PCV valve and remove it without pulling the ell out of the valve cover.

I just got up there yesterday, I'm not all that nimble... but didn't find it all that difficult to get to the PCV valve. But i started removing what was left of the Thermactor (smog air pump, for which I can't find a replacement in my country, so now it's gone) hardware, now I'm finding those hoses running to the back of the heads a pain, haven't been able to unplug them to place the threaded plugs you guys adviced.

Still-can't-reach-it

Signed

Greasy keyboard

I wanted to pass along my experience in replacing the PCV on a 1995 F-250 351. Hopefully, I can save someone a bit of time.

After much time spent with my arm wedged between the firewall, fuel injection plenum and A/C unit, I decided to try something that worked perfectly.

First, pull everything out - the elbow into the valve cover, the hose with the PCV in it, the vacuum attachment at the top of the PCV. Just yank it all out.

Now, replace the PCV after removing the hose clamp (I'm assuming you're looking at the picture of the whole assembly of the previous post).

Separate the assembly into two halves:

Bottom half = the PCV, the hose and the elbow that connects to the valve cover. Stick the elbow into the valve cover.

Top half = the vacuum attachment (this is the other, smaller elbow that has two vacuum connections - the top is capped, the other one connects to a vacuum line running into the fuel injection plenum). Connect this 'top half' of the assembly to the vacuum hose.

Now - once both 'havles' are installed - connect the top half (the vacuum attachment) to the bottom half (the half with the PCV on it). You're done!

The reason I'm taking the time to spell this out is that I spent too much time trying to piece it all together and wedge it into place in 'one piece'. The area is just too tight to do it that way. Breaking it down into two halves works well. Although I was afraid that connecting the two halves - at the point where the PCV meets the top vacuum elbow - would be difficult to accomplish - it's probably the quickest and easiest way to do it.

Another important note - I got into replacing the PCV because I noticed how dirty the throttle body was while replacing the TPS (another fun process). I heard from some Ford people that an incorrect or old PCV will result in a dirty throttle body. And now I know why so many are dirty - no one replaces the PCV!

Seriously, this worked well for me. Send an e-mail if you have any questions. Good luck.

You will clean up in a few days.

I posted the picture due to my surprise the PCV valve was not in the valve cover. I still wonder if the clamp on the bottom of the PCV could be loosened and not have to pull the ell out of the valve cover.

Yes, I am guilty of delaying PCV replacement for a couple of years. Hopefully we have made the process easier for everyone.

LOL, maybe this is something I would take to JiffyLube.

"Hey boys, got an easy one for ya'. No oil change, just pop in a new PCV for me, okay? I'll be right over here LMOA if you need anything."

Thanks for the write-up; it's now bookmarked just in case. Once I saw where the valve was on my new-to-me 351 I decided I wasn't going to bother unless I had a real reason to suspect it was bad. I'll save my knuckles and severe duty vocabulary for things that are actually broken. :-X22

stuck
 

So apparently i have something a little different on my 1996 f150. I am checking out some p0174 0171 codes and started with the PCV assembly.

What i found was that the place where the assembly meets the valve cover below the PCV valve is different that the picture in this thread. Instead of having a short 90 deg bend, i have some sort of cap which the hose from the PCV valve connects too. This is shown in my picture which is taken from the right side of bank 1. I think that there is the grommet underneath of this cap. You may be able to see a gap between the bottom of the cap and the valve cover. The cap is loose and I though might be part of the problem.

I can't get the cap or the hose leading into it, to remove. There doesnt seem to be enough space to get the cap out but i can feel it slide up and down...

Thoughts? why doesnt this fit tight? all i can think of is that someone replaced the factory stuff with aftermarket and it doesnt fit right....

http://s920.photobucket.com/user/sdshipe/media/photo11_zps3fd9844a.jpg.html?filters[user]=137675936&filters[recent]=1&sort=1&o=0

Well I'm not sure why you'd have something different on there, but I don't see why you can't just get a stock set up (new or from the local junk yard) and replace what's there.

I would definitely be doing that but I can't get the assembly off and I don't even know how it's attached on there. I was hoping someone could identify it so id know how to get it off. It slides up and down and can turn but it feels like it doesn't have enough clearance to come out.