anyone replace there expedition's PCV (i belive that's what's it's called) valve? i've knowned about this valve for some time now, but nevered replaced it in +100,000 miles. anyhow, i was the Autozone over the weekend buying a trans filter, fuel filter ect. and over heard this women behind the counter talking about it to another costmer about how he should replaced it for better gas mileage/ smooth idle. i was dumbfound to say the least, actually i was "schooled". i asked for one for my 97 5.4L expo, it was only 3 bucks. is this correct that this valve is replaced for good gas mileage/ smooth idle? and i noticed it's a small part(PCV), anyone know the location for this part on a 97 5.4L (classic) expedition? and at what intereval should it be replaced? thanks in advance!

-eddie

 

Yeah I need to change mine to. Iam over 100k as well. People told me it was to be replaced at 60k or 65k miles. I still havent done it.

 

Take the old one out and shake it - if it rattles it is ok - if it doesn't, replace it. They eventually get gummed up.

BTW, PCV = Postive Crankcase Ventilation and it has been around since the first emission controls (late 60's).

Ian

 

eddie, the pcv valve is generally stuck into one of the valve covers inside a rubber grommet. I've not really paid too much attention to my 5.4L, but I'm sure that's where you'll find it. The PCV acts kinda like a vacuum cleaner sucking "fumes" out of the top of your engine. You probably won't notice much performance/idle improvement unless you old valve was completely shot.

 

My owners manual states somthing like "dealer will replace PVC valve free at 60K mi " 1997 5.4l Mark

I don't go to the dealer for service so I may buy one

 

I had a vacuum leak on my 98 5.4L. The rubber hoses going to the PCV valve were oil soaked (internaly) and turned to mush. Half of them were collapsed and half were ripped open. THe only way to get them was to get the whole assy which included the rubber hoses, plastic tubing and PCV valve (30 some-odd dollars from the dealer). It sucked trying to install it (I had bloody knuckles to prove it), but I found out the PCV valve isn't in the valve cover. It has a hose attachment on the top and the bottom. The bottom hose goes to the valve cover. It's on the passenger side towards the rear.
It must have been like that for a while, cuz we bought the truck used and it ran better than it ever did after replacing the hose & valve assy.

 

replaced mine in my 99 5.4 a few weeks ago during an oil change. <$5 from pep boys and about a five minute change. mine did sit in a rubber boot on the rocker cover.. i remembere it was on the passenger side, just under where just about all hoses and cables converge 2/3 the way back on the cover.. the old one was fine at 140k, but with the cost and effort involved ....

 

Mudman is right about the pcv hoses.. It is very common for 5.4's to rot out the elbow on the back of the throttle body where the line from the PCV valve connects. Most of the do it at the 100K plus mark. This will cause a huge vacuum leak and will cause a check engine light with the codes of right and left bank lean and sometimes a Mass airflow problem, because of the unmetered air getting into the system. Also causes rough idle.
Reach way in the back and feel of it,, if it feels like mushy sticky rubber then its time... If its really bad off,, with the engine running you will feel engine vacuum with your fingers.

The dealer is the only place to get the whole assembly, it comes with all the lines and the valve. Got mine for 20 bucks.

 

Does this happen on the 4.6 as well??I have a pinging problem
that is driving mre nuts.This POS has pinged ever since I bought
it.Even with 92 octane does it ping and no codes or CEL.

 

You might want to check for clogged EGR ports on your pinging 4.6
From what I have read its very common and pinging is a side effect of it.

 

Anybody who knows the partnumbers for "the whole assembly" ?
i'm living in norway and i don't see many f-150s here, so i'll have to order the parts from the US directly.

 

..2004 Ford Expedition with 65000 miles, a 4.6 engine....it is revving up the motor , RMP to 3 and the check engine light came on. We had 2 diagnostic test done, first one stated the 1 and 2 plugs were running lean, and the 2nd time the oxygen sensors were bad. we had a oil change, replace fuel filter and air filter, idle air control, replaced oxygen senors, replaced throttle position sensor and clean out the throttle body, replaced the PCV hose . The check engine light has gone off but its still revving up . Can anybody tell me what is causing this?