PCV valve education
#1185741
02/25/12 12:24 PM
02/25/12 12:24 PM
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Joined: Mar 2005
Posts: 862
Iowa State fan
kilroy
OP
super stock
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OP
super stock
Joined: Mar 2005
Posts: 862
Iowa State fan
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Ok I know the gist of the PCV valve operation (or I thought I did)
couple of questions...
With all the talk of PCV on 4.7 engines and with my Durango and using some oil mysteriously lately (which is not showing up on the plugs) I thought it was time to clear the water on a few questions.
1. Should a PCV valve have full vacuum present on the motor side of the valve at IDLE, or should it be sucked closed?
2. What are the symptoms of a stuck open PCV?
3. Does anyone know if the PCV on a 02 Durango is spring loaded or is it just a "rattle" valve?
1973 Charger, former SE, former auto
I'm not trying to be difficult, it comes naturally....
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Re: PCV valve education
[Re: kilroy]
#1185743
02/26/12 12:16 AM
02/26/12 12:16 AM
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Joined: Oct 2005
Posts: 4,946
WI
Dcuda69
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master
Joined: Oct 2005
Posts: 4,946
WI
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Re: PCV valve education
[Re: Dcuda69]
#1185745
02/26/12 12:26 AM
02/26/12 12:26 AM
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Joined: Mar 2005
Posts: 862
Iowa State fan
kilroy
OP
super stock
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OP
super stock
Joined: Mar 2005
Posts: 862
Iowa State fan
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Ive got full vacuum at idle in my durango. When I put my finger over it I can hear the valve snap inside, but It has FULL vacuum at idle and I couldn't get a straight answer googling things. Would this cause some oil consumption.
1973 Charger, former SE, former auto
I'm not trying to be difficult, it comes naturally....
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Re: PCV valve education
[Re: kilroy]
#1185746
02/26/12 12:35 AM
02/26/12 12:35 AM
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Joined: Oct 2005
Posts: 4,946
WI
Dcuda69
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master
Joined: Oct 2005
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WI
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Quote:
Ive got full vacuum at idle in my durango. When I put my finger over it I can hear the valve snap inside, but It has FULL vacuum at idle and I couldn't get a straight answer googling things. Would this cause some oil consumption.
That sounds pretty normal....if in doubt just replace the valve(with the correct, quality part)Don't forget to check the fresh air side of the pcv system.  
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Re: PCV valve education
[Re: kilroy]
#1185749
02/26/12 03:28 PM
02/26/12 03:28 PM
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Joined: Jan 2006
Posts: 8,162
USA
360view
Moparts resident spammer
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Moparts resident spammer
Joined: Jan 2006
Posts: 8,162
USA
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It was interesting that on the cast iron 8l v10 Chrysler went with a fixed orifice instead of a rattle type PCV Here s another variation http://www.envalve.com/why.htmlIn theory Having a low vacuum inside the block During part throttle cruise Would give a slight fuel economy benefit ... The backside of the piston would not be fighting against a pressure and internal moving parts would encounter "wind age" aerodynamic losses
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Re: PCV valve education
[Re: kilroy]
#1185750
02/27/12 09:59 AM
02/27/12 09:59 AM
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Joined: Jan 2003
Posts: 541
chatham, Ilinois
fox
super street
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super street
Joined: Jan 2003
Posts: 541
chatham, Ilinois
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Quote:
Ive got full vacuum at idle in my durango. When I put my finger over it I can hear the valve snap inside, but It has FULL vacuum at idle and I couldn't get a straight answer googling things. Would this cause some oil consumption.
A stuck or imoperative PCV valve can cause a motor to gum up and then use oil.
But, I've never seen one working cause it.
The PCV valve really never completely closes, tha tI've seen. They open fully at low vacuum/WOT.
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It sounds like yours is operating correctly, vacume is high on stock motors at idle, you put your finger over the PVC end and the spring inside did its job, it closed the valve 
Their designed to suck the bad fumes out of the crankcase when the motor is running, they do a outstanding job of sucking any water or condensation out of the motor also 
