Clogged screen under PCV valve = oil leaks

wagstdy · 02-26-2003

I learned a valuable lesson from 7DMACH1 about the wire screen under the PCV valve and thought I'd pass it along in a new thread. I'm thoroughly convinced that the clogged screen under my PCV valve was the root cause of all the oil dripping from my engine. If you have any fresh oil running down the side of your engine or on the ground, read on before replacing any gaskets or seals.....

1. Get a stool and lean over from the passenger side of the car. If you get your head directly above the back side of the intake and all the way against the hood, you can see the PCV valve.
2. Carefully disconnect the two small vacuum hoses on the back side of the upper intake directly above the PCV valve. These plastic tubes get brittle after a while so watch out!
3. Pull the PCV valve out. The rubber grommet under the PCV valve might come out with the valve. If it doesn't, you should be able to stick one of your fingers in there and pull it out. If it is stuck, you might be able to grab it with a needle-nose plier.
4. Spray the exposed screen with carb cleaner to loosen the grime and varnish. Get a long needle nose plier and grab one of the three tangs on the top side of the screen. Luckily it worked for me but it was like performing surgery. My next option was to screw a 3" wood screw into the screen about 1/4" and then use that to pull it out.
5. Once I got it out I used about 1/2 can of carb cleaner to douche it out real well.

7DMACH1 says the dealer sells them (if you ruin it while taking it out or don't feel like cleaning it).

GTRaptor · 02-26-2003

Nice tip, thanks

RiceBurner · 02-26-2003

i didnt know you could leak oil like that. Makes since tho.

wagstdy · 02-26-2003

Forgot to mention why....

PCV stands for Positive Crankcase Ventilation which is a smog system that allows the gasses in the crankcase to pass into the intake and be burned. If that screen under the PCV valve is clogged, pressure from the gasses will build and escape out the path of least resistance which will be one of your gaskets or seals.

One way to tell if your screen is clogged (assuming your PCV valve is working correctly) is to take your PCV valve out and listen for a change in RPM. If there is no change in RPM (again assuming your PCV valve is working) then your screen is OK. If the RPM surges when you pull the PCV valve out then the screen needs cleaning.

YardSpecial · 02-27-2003

Also available at the dealer for cheep!!

7DMACH1 · 02-27-2003

They retail for $7.31 at the dealer. The other thing it helps is if the screen get clogged it can cause the IAC or air bypass valve to get slugged up. This screen is an important part of maintainance. It should be replaced about every 30,000 miles.

brisk_tea · 02-27-2003

you paid $7.31 for the 'birds nest'? you can get them for less than a dollar or just over a dollar at any auto part store...
be happy you were just leaking oil... when mine got clogged, oil was sucked into the intake and a lot of sensors got messed up...

ex0r · 07-26-2009

I just replaced my stock PCV valve today with a replacement one. The car runs ALOT better, but still sluggish every now and than. I stuck my finger in the opening and could feel the screen, but can't seem to get it out. It felt like it was caked with oil, so I scraped what I could off the screen with my finger.

The screen feels like it's warped (you can feel ripples in it). If I take the screen out and leave it out, will it hurt the car any? Guy at autozone said he has never heard of there being a screen in there, and couldn't find one to replace it with.

ttopstang · 07-26-2009

there is a screen in there, im not running one right now because i got in an argument with a guy at autozone about it having a screen and he said theres no such thing.

ex0r · 07-26-2009

So how do you take it out? Does it hurt anything leaving it out? It looked like there was a little metal tab on it that you could grab onto and pull out, but it's been in there so long (stock from 100k miles), so it's probably going to be quite nicely stuck in there. Somebody else recommended using needle nose pliers to grab onto the tab? That's in there quite a ways, don't think you can get pliers in there.

redwalsh87 · 07-26-2009

Quote:

Originally Posted by ex0r

So how do you take it out? Does it hurt anything leaving it out? It looked like there was a little metal tab on it that you could grab onto and pull out, but it's been in there so long (stock from 100k miles), so it's probably going to be quite nicely stuck in there. Somebody else recommended using needle nose pliers to grab onto the tab? That's in there quite a ways, don't think you can get pliers in there.

Don't forget to remove the rubber grommet which holds the pcv valve itself. Without removing this you will have a lot more trouble removing the screen since the screen is below the rubber grommet. Mustangs Unlimited sells the screen too...

choppin · 07-26-2009

hey whats up? I had the same problem with partsmen at auto zone, pep boyz,and advance auto. they never seen such part. so i back to advance and told them that i need a crank case filter. plus i gave them my old one to look at. finally they knew what i was talking about. the answer to your question is yes you need to go back with one. reason the sceen filter prevents sludge passing through the pcv valve. to remove the filter use a long steel wire thin as a fishing hook bend a hook just pull it out. i hope this helps.

fbca7 · 09-25-2009

This was a new one on me. It even shows the screen in my shop manual but it makes no reference to it. I just bought a 93 vert with 123,000 on the clock. I use almost a can of carb cleaner on the screen. Ran the car for about 20 miles today, came home to a dry under side. I might add I also replaced the pcv hose (which appeared original), pcv valve (which was a motorcraft and could have been original) and the grommet. Thanks for the tip.