Where is the pcv valve located? - Jeep Cherokee Forum

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Where is the pcv valve located?

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Old 02-21-2009, 11:42 AM
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Default Where is the pcv valve located?

i was going to replace it soon and i cant find it.... anyone know where to find it? thanx
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Old 02-21-2009, 12:06 PM
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Originally Posted by snowmonsterdude View Post
i was going to replace it soon and i cant find it.... anyone know where to find it? thanx

follow the hose from your valve cover to your air box .. take the lid off the airbox and its where that hose connects into it
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Old 02-21-2009, 12:27 PM
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I thought it depended on the year?

Neither my son's 96 nor my '97 seem to have one.

When i look in the reference books at Autozone, they show it as "NR".
As in "not required"???
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Old 02-21-2009, 12:45 PM
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well... if it does have one it is where i said.. i have a 88 and a 95 and they both have em
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Old 02-21-2009, 02:31 PM
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On my 1990 it is the connection of the valve cover to the hose that runs to the air box, so thats a different location. Yours is a 98 so not like my info helps much, but at least now you know
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Old 02-21-2009, 03:23 PM
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My 99 dose not have one. I dont believe 96-2001 have PVC valves
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Old 02-21-2009, 06:33 PM
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it should be on top of the valve cover, where that air hose connects, but i dont think it's a servicable part...for your year model at least

Last edited by HxcJohnny; 02-21-2009 at 06:43 PM.
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Old 02-21-2009, 07:54 PM
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You don't have one. All 4.0L engines (1987-forward) use what is called "Constant Crankcase Ventilation" (CCV) - there is a constant small supply of "fresh" air going in at one end, and a slight constant suction on the other. I don't recall which is which, but I believe the smaller hose is the supply line and the larger one up front is the suction into the intake stream.

If you're having problems, give us symptoms to help you sort it out. If it's a maintenance issue, the most you usually need to do is blow out the lines with carburettor cleaner and remove the baffles from inside the valve cover and clean them out - usually to correct an issue with oil collecting on the air filter.
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Old 02-21-2009, 08:39 PM
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You don't have one, and don't try to remove either of the hose connectors or grommets from your valve cover. They will more than likely crack and not come off with out you destroying them. This just happened to me and I had to buy the grommets and CCV/vent in order to replace them. This is not a serviceable part.
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Old 02-21-2009, 09:28 PM
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Originally Posted by 5-90 View Post
You don't have one. All 4.0L engines (1987-forward) use what is called "Constant Crankcase Ventilation" (CCV) - there is a constant small supply of "fresh" air going in at one end, and a slight constant suction on the other. I don't recall which is which, but I believe the smaller hose is the supply line and the larger one up front is the suction into the intake stream.

If you're having problems, give us symptoms to help you sort it out. If it's a maintenance issue, the most you usually need to do is blow out the lines with carburettor cleaner and remove the baffles from inside the valve cover and clean them out - usually to correct an issue with oil collecting on the air filter.


5-90, you have it backwards....

The rear line has the small plastic one way valve that goes to the intake runner. So that is the suction line. The inlet is the front one that attaches to the airbox. I always heard it called Closed Crankcase Ventilation, though.
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Old 02-21-2009, 09:46 PM
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First, not to sound like a cool guy but get a good repair manual. Its called the Positive Crancase Ventilation system PVC. You can replace it but most likely you'll want to take the valve cover off. I have never had one come off and not break. Just my 02.
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Old 02-21-2009, 10:22 PM
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jeeps don't have a pcv valve. they have a ccv system.
there's no check valve, it's just an open tube.
it takes clean air from the front of the airbox and puts the unburnt mixture back into the intake.
that's why a clogged rear line will cause oil to build up in the air filter.
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Old 02-21-2009, 11:38 PM
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So what do I do if my newly purchased XJ has the line coming off the valve cover to a plastic valve and nothing else hooked to that valve? haha So Can you just run a breather on the valve cover? Im new to Jeeps sorry
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Old 02-22-2009, 07:01 AM
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Originally Posted by ShortyzKustomz View Post
So what do I do if my newly purchased XJ has the line coming off the valve cover to a plastic valve and nothing else hooked to that valve? haha So Can you just run a breather on the valve cover? Im new to Jeeps sorry
The line from the plastic check valve goes to the intake runner. Look on it between the throttle body to where it would enter the number one cylinder. There will be a small port on the top. That is where it is supposed to connect. When you find it, take the opportunity to pull the port out and clean it. Many times it will be clogged with crud.
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Old 02-22-2009, 09:16 AM
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in the 4.0's ccv system the rear orifice on top of the valve cover has a metering device that can become clogged but you would probably be getting some blowby if it was...and it is a dealer part only..and yes i ran just a breather on the front orifice on the valve cover of my xj
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