PCV Valve Mystery on VQ35DE

[WAPathy]

Hey all,

 

I replaced my PCV valve in my 03 Pathfinder while I was locktite-ing the power valve screws. I ordered a PCV valve (AC Delco CV941C) prior to beginning the procedure, but found that it was not the same as what was in the engine. The threads and overall dimensions were different than the original part. This lead to a trip to the local parts store. Their computers showed yet another variety of PCV valve that was not like what was originally in the engine. They recommended a model that did not have threads (FRAM FV373). The PCV valve that I eventually used was a Airtex 6P1238, which has threads that on the valve cover side.

 

My Pathfinder has 75k miles on it. I bought it when it had 22k and suspect that this is the first time the PCV valve has been replaced.

 

Long story short... does anyone know why there appears to be different PCV valves for the same VQ35DE engine? Has the design of the PCV valve changed over the life of that engine?

 

Secondary question, I read somewhere to replace PCV valves every 30k-50k miles. Does this seem like a reasonable interval?

 

Thanks!

Bryan

[ronin152]

Hey all,

 

I replaced my PCV valve in my 03 Pathfinder while I was locktite-ing the power valve screws. I ordered a PCV valve (AC Delco CV941C) prior to beginning the procedure, but found that it was not the same as what was in the engine. The threads and overall dimensions were different than the original part. This lead to a trip to the local parts store. Their computers showed yet another variety of PCV valve that was not like what was originally in the engine. They recommended a model that did not have threads (FRAM FV373). The PCV valve that I eventually used was a Airtex 6P1238, which has threads that on the valve cover side.

 

My Pathfinder has 75k miles on it. I bought it when it had 22k and suspect that this is the first time the PCV valve has been replaced.

 

Long story short... does anyone know why there appears to be different PCV valves for the same VQ35DE engine? Has the design of the PCV valve changed over the life of that engine?

 

Secondary question, I read somewhere to replace PCV valves every 30k-50k miles. Does this seem like a reasonable interval?

 

Thanks!

Bryan

I also have an 03 pathy with 71K milles. I don't believe you even have to change the PCV valve. In the service manual it says change PCV only on the xterra and frontier. I don't think you even need too unless you get a check engine light....

Edited February 8, 2009 by ronin152

[180sx]

Yea, why would you change the valve? i have 152K on my pathy, and havent changed mine. Theres no need. The only thing i have changed is one of my Valve Cover gaskets (even though a few things still are pending, but nothing serious at all. That VC gasket was leaking oil on my exhaust manny and making it smoke!).

[02silverpathy]

If you pull your intake manifold on a VQ35 you will see quickly why you should change this piece of poo. My upper intake was a b-e-a-utiful color bronze---problem is that the parts are aluminum. The PCV in the VQ sucks bad and in fact the valve cover baffles are so bad on the pass side valve cover that versions have come out from Nissan to replace it.

 

Oil flows freely through the PCV and clogs everywhere...aiding this engine to consume oil. I found the EXACT same issue with my PCV so I took min out, popped it into 2 pieces ( I think it can be done once), cleaned it and snapped it back together (again it is all plastic and probably will not survive a second cleaning). Next I ran a new slightly larger "fuel" line to an actual filter/container (it is a fuel filter that has clear plastic and filter media) to filter vapors and catch oil. Then from this filter to underneath the TB.

 

I catch probably 1-2 ounces of oil every 3K miles, at which point I pull the filter since it is small and any more would allow the oil to go into the TB, dump out contents and spray brake clean until it is clean again.

 

2 weeks ago I pulled my TB while checking my plugs and after 11K miles this has kept my intake manifold very clean and free of oil bronzing. There is still a light slippery feeling inside, however nothing like before.

 

Wann see more? Check out Ventec's scary pics from his power valve adventure. Particularly http://img.photobucket.com/albums/v316/Ven...er/IMG00146.jpg

 

In addition a larger pic (thanks Ventec) shows the overall power valve area...the only thing in this pic ths should be bronze is the butterfly's, and hopefully their screws (Dude I am sorry that happened to you).All the butterflies.

 

That little hole is the entry point from the PCV valve into the throttle body....your intake air belongs here...not oil!

Edited February 8, 2009 by 02silverpathy

[laxman0324]

Hey Chris, can you replace the PCV valve without removing the intake manifolds? The PO had a new PCV valve that he gave me when I bought the truck, unfortunately I didn't read between the lines quick enough and my VQ is burning a LOT of oil. You want to try and do the valve covers together this summer at some point?

[02silverpathy]

There is not enough hand space to get the current PCV out. The oe install also requires a bit of strength to remove it also.

Sounds sweet on the valve covers, I just need to see if there are other options for the covers...$152+ is a lot of dough for covers (that is a piece!). We can pull your stuff, swap the PCV and add my little filter due-hickey whenever you want...PM me and we'll get a day planned! I would reccommend my place, until I buy a house I rent a massive garage...nearly 40' x 40' (38x36??).

[laxman0324]

Well I added 5 qts 6k miles ago and 1 qt 5 or 600 miles ago, and I just changed my oil and I got out 3.5 qts, so assuming it did not burn much of the last qt I added it is burning less than .5 qt per 1k miles. Not good but not as bad as I was expecting. And the oil was dirty as hell. I think I will shorten my oil change interval, and I will PM you in early June after we get back from our vacation to Disney about meeting up to do this, I am capable of doing it but feel more comfortable with someone who has already done it...And coming to your place is not a problem...

[180sx]

Your filter duhickey is basically an oil catch can. Works wonders.

[02silverpathy]

Exactly!

You tried this also?!

It really keeps the intake clean!

[tropia]

Exactly!

You tried this also?!

It really keeps the intake clean!

 

Hate to dig up this semi old thread but 02silverpathy, do you have a pic or something to help me set up this filter? I just took off my upper pendulum tonight and it looks even worse than those pics you posted.

 

Just looking to do this to mine and was looking for a bit more info before I went to the auto parts store to look for the filter and hose.

 

Thanks for the help

[02silverpathy]

I do not have a pic of my set up, but it is easy to type up.

 

The hose leaving the PCV connects to your throttle body...right beneath it actually. In its path it also uses a small brass colored metal line that bends arouns the intake. I took this metal line off and used new fuel hose from the pcv to a small open space close to the brake booster, this is where my "catch can" resides.

 

I do not have the catch can mounted at all, the fuel hose is rigid enough and the filter light enough to hold it in the air against this tiny open space. I have had the same catch can (fuel filter) for over a year now and it works great. When I change my oil I diconnect the can and spray it clean with brake cleaner so I can see when it fills again.

 

The reason I used a fuel filter is that it was small fit perfect, I can see through it (for the most part), and it has a filter to catch the oil vapors. I found a pic that is close to what I am using and it was an off the shelf part at AutoZone.

 

"Catch Can"

Edited July 28, 2009 by 02silverpathy