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-   -   How To: Clean your PCV valve (http://www.jeepgarage.org/f5/how-to-clean-your-pcv-valve-23124.html)

Jahkneefive 05-12-2011 10:18 AM

How To: Clean your PCV valve
 
Ok well I've see the question/comment pop up in several threads about cleaning the pcv valve in the hemis. Well good news you can indeed clean it. Now this is assuming its not COMPLETELY gunked up to the point where the brass slider won't move at all, but even if it is there is a slim chance you still can.

Ok first how the pcv operates. Inside the plastic housing there is a metal rod that runs the length of the valve. On that rod is a brass slider that goes up and down, think of it like and old school slide ruler. when there is positive crank case pressure that brass slider goes to the top(the wide end) of the pcv allowing the extra pressure to travel through the valve to the hose, and finally back into the intake. When there is negative pressure the slider is sucked to the bottom of the pcv and seals it shut, not allowing any air back into the crank case.

Very simple design yes, but also a very easy design to fail/clog. What happens is that over time the oil that naturally travels through the valve with the excess air pressure starts to gunk up, much like engine sludge in the oil (mixture of engine oil and combustion carbon), inside the valve passage. As you can imagine since this valve has to seal shut under vaccum, there are very tight clearances, meaning even the slightest amount of carbon/sludge build up will prevent the slider from sliding up and down the rod smoothly or in some cases at all. The slider getting stuck is what causes issues as it doesn't allow the crank case to vent the pressure or maintain a vaccum, both important to performance, fuel mileage, and idle conditions.

Step 1: So step 1 is to shake the pcv and see if you can here the slider rattle back and forth. If you can good news skip to step 2 as your's will be easy to clean. If you cannot then goto B.
B. First I wil tap the valve lightly on a hard surface to see if you can't free up the obstructions. If this works goto step 2.
C. If the tapping didn't work, you now need to get out your citrus degreaser and soak the whole valve for a good 15 minutes. If after this step its still stuck, give up and just buy a new one.

Step 2: Break out some citruss cleaner(I'd stay away from petroleum cleaners ie brake parts cleaner as they tend to degrade the soft plastic and pit the brass slider). Now soak the valve makign sure to spray into both inlets/outlets. Then shake it back and forth in your hand. do this several times until the slider seems to move freely. You should notice some dark fluid coming out after the 2nd or 3rd spray down. After you're convinced its clean wash it off with water and let it dry.

Step 3: Now to test your job. hold the pcv so its vertical and suck on the bottom end. If its clean the slider will already be at the bottom thanks to gravity, but it should make a fairly strong seal. In other words when you suck on the end very little if any air should be pulled through. If you can suck air through it extremely easily then go back to step 2 and try cleaning it some more. If its still not sealing well the 2nd time on this step, you'll need to replace it as the mating surfact between the slider and the bottom of the valve housing is trashed.


One note I'll add, but not recommend as I'm sure its bad for me, is if the pcv slides fairly easy in step 1, I'll actually wipe it off and suck on the end ahead of cleaning, just so I have a gauge in step 3 to compare the final result against. If you do this I highly suggest you blow out very strongly on the valve first to blow out and loose debris.

As far as when to do the cleaning, I do mine about every 6-8K miles as it keeps it from getting so gunked up that it can't be cleaned. Eventually you'll still end up replacing the pcv, but this genearlly keeps mine working for much longer.

Final Tip: Pay attention when you pull it out, you'll notice that there is a small hole at the top that lines up with the exit nipple on the surrounding housing. Some people have managed to install this backwards with the hole facing towards the firewall, which suprise suprise will causing running issues.
This is the version 1, so please excuse any typos. The plan is to re-read it tonight and make any corrections that need to be made.

08Hemi 05-12-2011 10:32 AM

Re: How To: Clean your PCV valve
 
great write-up....+rep

Walt 05-14-2011 08:42 AM

Re: How To: Clean your PCV valve
 
Quote:

Originally Posted by Jahkneefive (Post 413638)
.....you'll notice that there is a small hole at the top that lines up with the exit nipple on the surrounding housing. Some people have managed to install this backwards with the hole facing towards the firewall, which suprise suprise will causing running issues.....

Nice write-up. Thank you.

Question: You stated installing the valve body with hole facing aft (on my 5.7L HEMI anyway) may cause performance issues. What performance issues might I expect?

When I took my PCV valve body out to examine it, this is the way it was installed at the factory, so I've replaced it that way ever since. FSM is silent on this orientation.

My Billet Technology oil catch can is collecting plenty of oil (:() so I'm assuming it's open enough to pass the vapors.

Jahkneefive 05-14-2011 10:10 AM

Re: How To: Clean your PCV valve
 
The way it was explained to me is that there is a small passage way all the way around the top lip of the housing that over time may clog/gum up with the same stuff that clogs the actual valve; impeding the path of the air to the exit hole. By lining it up directly with the hole it prevents this from ever happening. So with a clean pcv and housing I doubt you would ever have an issue, its later on when everything starts to get dirty that problems may or may not arise.

Now reason tells me that by the time the top starts getting clogged the actual valve is probably stuck anyways, so you'd be pulling it out to clean regardless. BUT on the flip side (get it flipping the valve har har har) turning it to line up with the exit hole doesn't cost me anything so...

SvenskaJeepGuy 05-14-2011 10:11 AM

Re: How To: Clean your PCV valve
 
they are super cheap, much easier to replace it.

Djsal5 05-16-2011 12:27 PM

Re: How To: Clean your PCV valve
 
yea replace it i paid 3 bucks but cleaning it is ok i guess

Chaoul1 05-16-2011 12:36 PM

Re: How To: Clean your PCV valve
 
I really want to do this to my Jeep. Could you or someone provide pictures! :D

Walt 05-16-2011 07:06 PM

Re: How To: Clean your PCV valve
 
Quote:

Originally Posted by Djsal5 (Post 415742)
yea replace it i paid 3 bucks but cleaning it is ok i guess

..for the 4.7L V8. For the HEMI, it's $25-$35.

Mine has always been very clean (oily, but clean). No sludge or mayonaise.

Oil catch can got some mayo (emulsified oil/water condensate) this Winter, but it went away with Spring. Now I'm back to 5W-20 synthetic oil in the oil catch can (yummy).

SvenskaJeepGuy 05-16-2011 07:28 PM

Re: How To: Clean your PCV valve
 
but it is a 30k mile part, so $25-$35 is not alot to pay. are you guys also cleaning your oil filters?? they are $6 and only last 3-7k miles HAHAHA

Jahkneefive 05-16-2011 08:39 PM

Re: How To: Clean your PCV valve
 
lol, bad analogy, you can't clean the filter media, its designed to bond with the particles that precipitate out of oil. AND i do mine while I'm waiting for the oil to drain, literally takes me 3 minutes to pull it spray it down, shake wash and dry. Then when I get done filling up the oil its dry and ready to put back in. Id bet I'm able to get atleast 90K out of mine, so its now a $120 savings for 12 minutes of total time. So 12 minutes sounds better than the ~7 hours the average american would have to work to pay for the 3 pcvs I was able to eliminate. :P And yes I'm aware you were just joking, I'm just pokin back at ya.

Walt 05-17-2011 07:30 PM

Re: How To: Clean your PCV valve
 
Quote:

Originally Posted by Jahkneefive (Post 415995)
lol, bad analogy, you can't clean the filter media, its designed to bond with the particles that precipitate out of oil. AND i do mine while I'm waiting for the oil to drain, literally takes me 3 minutes to pull it spray it down, shake wash and dry. Then when I get done filling up the oil its dry and ready to put back in. Id bet I'm able to get atleast 90K out of mine, so its now a $120 savings for 12 minutes of total time. So 12 minutes sounds better than the ~7 hours the average american would have to work to pay for the 3 pcvs I was able to eliminate. :P And yes I'm aware you were just joking, I'm just pokin back at ya.

X2. :metoo: BTW, it's 60K mile check on the '08 WK's. I look at mine every 30K miles.


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