Thanks to navygz19 for the heads up on this. i have started a new topic as I feel this is extremely important for VQ35 owners.


The background is here

In short, the 6 butterfly vales, held in with 2 screws each, can come loose and destroy the engine.

I have done some research on this and here is what I found:

The Kamloops Nissan dealer has quote "done quite a few of these" un-quote, so it is an issue.

It is the screws holding the butterfly valves, in the upper manifold. Approximately 3 hours to fix. The fix? Remove each screw and loktite it.

My truck is booked at my local shop for Monday to have this done, will update then if they found any loose or missing screws.

thanks for the heads-up. did you happen to get a price quote?

Great, now mayhem is sure to follow
I think it's important to add that this is a farily sporadic occurence for the VQ. It's NOT a common problem, though if your Pathy falls victim to it the damage is irreversible.

It simply amazes me that the VQ can have this same issue as the QR25DE I had in my Sentra. And by same, I mean exactly! I blew an engine due to this very same problem which was (thankfully) replaced by Nissan under powertrain warranty (all 118 miles of it that was left at the time)
The most disturbing part about it was that upon checking the screws myself in my replacement engine (which subsequently was an '05 in my '02 and, according to Nissan, had the problem "remedied") I found them to be loose again, with no loctite at all. I did it myself, but I'd never try it on a VQ.

see my previously edited post ^^
The Altima has the same engine as the SE-R Sentra's.

One other thing the dealer mentioned was that if "just" a screw falls out, good chance you will not notice. As it is brass and relatively soft, it will often just get chewed up and spat out the exhaust. It is when the valve drops out you lose the motor.

True, but brass or not, I'm sure that would be enough to scour the hell out of the cylinder walls. When it happened in my Sentra, I lost my #3 cylinder in a tunnel. The spark plug had been hit with the screw itself and the electrode was bent all the way down. Running on 3 cylinders to get the hell out of that tunnel was the most fun I've had in a 4 cylinder!
And thus is the importance of regularly checking and changing oil

*Update*

Anyone who owns a VQ powered Pathy, please go out and check your oil level! Isn't it all too ironic that the day I find this bulletin information I find that MY truck itself is down on oil. After posting to the other thread I checked my level, and it was just barely above the low mark. The Pathy hasn't been driven in two days, so I drove it for 5 mins. to warm it up and checked again...same thing, just above the low level.
I change my own oil w/ 10W-30, every 3K miles, religously. I DID, however, just put about 2K all highway miles on it over the holidays, but the oil was changed right before I left.
It's gonna be an arduous journey guys...

This is a known issue, everyone please go out and check! I don't want to see someone's Pathy's sitting on the side of the trail w/ an engine that's run dry.

The work is done, 2.7 hours (less than the quote), no missing screws

All are lokited. The mechanic and manger, once it was opened up, could see why it could be a problem. I am happy it is done

Have you noticed any oil consumption, Train? The PCV valve is another issue that's a little harder to diagnose...

Mine's going onto the shop tomorrow to be torn down to see why it's burning so much oil. I knew there was a good reason I bought an extended warranty.
If I said I weren't a little nervous about what they find I'd be lying

do we know if this problem is isolated to 2002 and later? i have an 01. i called one local nissan dealer and was told 'nissan has no knowledge of this problem.' they are clowns though...

I did call make that call NNA and all I got in response was "there is no current campaign on the Pathfinder, with the power valve situation" This item would be covered under a workmanship defect in the factory warranty and also the Nissan Pre-owned perferred warranty, which must be purchased the day the vehicle is purchased from a dealer wether new or used. I was also told that I would be exremely happy with the VQ powered Path as it has had very high reviews from many many Nissan customer.

***EDIT***
Trainman, approx what did your pre-issue maintainence cost you? It sounds like extra cheap insurance!

Can anyone give a further clue as to what has to be removed to get to these screws? The less you remove from the motor the better chance of future issues...I may be speaking from experience! Lol!!

Upper Intake manifold, and all associated components for it's removal. If it's anything like my Sentra, pop it open and VIOLA, there's the valves, all 6 of 'em.

The Sentra had 2 screws per valve, I'm assuming the VQ's the same?

Are there any symptoms that the valves may be coming loose or operating improperly? Forgive me as I'm not familiar with the operation/purpose of these valves.

The reason I ask is that upon startup, or approx 15-20 seconds after I start my 01 Pathy, it begins to sputter, sounding somewhat like a misfire condition. This lasts for approximately 15-30 seconds, then the engine comes back to normal and the engine has all the power it normally has.

I have pulled the code for the MAF sensor and a new one will be on it's way very soon, but I'm somewhat doubting this to be the cause.

Any advice here?

Very very occasionally mine does that doo but only on very cold days, particularly if it wass very warm the day before. A constant sputtering however would suggest a bad valve that can't hold compression but it doesn't sound like that's the issue w/ yours.

would this problem also apply to a 2003 infiniti g35 it's the same engine right?

yes, it is the same engine, but I haven't done any sort of research on the Infiniti line w/ this engine (FX35, G35, M35)

Good, this is finally pinned.

Anybody do this job themselves? If so would they be willing to do a step by step walk through on it with some pics or diagrams ?------This seems important enough to warrant this, especially for us who do not have warranties still in effect and who cannot afford to have their motors severly damaged.

Yeah, Jarsiff did it a few weeks ago, maybe he could write some sort of a procedure for this...

Well couldnt wait any longer, was sweating bullets on this one , so I went out and took the plunge and locktited all the power valve screws, wasnt too bad a job actually, took about 1 1/2 hours to do, feel loads better, all the screws were tight , and seemed to have some kind of thread lock on the threads already, I am assuming it was from the factory because it does not appear that the intake and surrounding paraphanelia has ever been took off before. But now I know for SURE that they are all tight and with thread locker!! Now to figure out how to resolve my oil consumption problem.

Yeah, Great. Now how did you do it? You guys have me freaking out now LOL. I just put all this money into lifting my 02', and now i hear the engine could blow. Good grief. Could you post some details please? What year/model was your truck. It's interesting that you found locktite. I'm sorry i can't offer you any help with your oil consumption problem. It's either burning, which it dosen't appear to be (no smoke) or leaking somewhere. If not on the ground, then into your system. thanks for any light you can shed.

Pete

2001 pathfinder , just emailed navygz19 with the procedure on how to do , email him for a copy of it , and Ill try to post later, ( running late for work at the moment). Was a very easy , straight forward and not technical procedure, do not be overwhelmed---and gives PEACE OF MIND when done. The oil prob appears to be a design flaw in the valve cover baffles that trap oil and allow it to be siphoned out the PCV , only fix is to install valve cover that has different baffle it appears.

Thanks a ton. I'll email him. Now how the heck are you supposed to find a valve cover with a different baffle design? That sucks. But why don't i have the problem and you do? Mines only a year newer. heck, alot of us have this truck, and i haven't seen much about oil consumption, but i haven't been looking either. Anyway, thanks again.

Though I am helping, we are heading off topic...however, to stop oil from going through the PCV line should be a small pipe cleaner looking part in a hard line that will stop oil from returning all the way through. I only know this because of my late 3.3. When I replaced the Dizzy the hard PCV line came off also to get a good cleaning and found there to be much sludge and this pipe cleaner thingy that my shop said to put back in that it was for this exact reason. I don't see why you couldn't add this to another line if you wanted to, you just need it to be a snug fit so it could not relocate itself!

I would start by checking HERE . This looks like a decent site and I've already had a few replies for various parts I've requested info. for. Plus, there are more Pathy's on this site than any other I've ever seen.

In addition, check page EM-10 in the Pathfinder FSM for a detailed view of the IM, TB and all hardware along with the torque specs. for everything.

nice

this is the kind of thing you're glad to know but wish you didn't know.

heres the thread where i was talking about it grr post i actually used the haynes for this one is it was pretty straight forward, the only real pain part is in the rear passenger side of the lower im if your taking it completely off is slow going with the two bolts and no room to maneuver around them but if your only mission is to check the screws than 1 to 2 hours tops and the only thing i did was had some room to lay out the bolts that came out so i wouldnt mess up the order. you only have to take off the upper half of the plenum and there are two gaskets there along with the TB gasket, all are fairly cheap.

Can somebody post a link of a technical manual showing those screws with the torque that they need. I have an appointment next week to get it done but the guy looked like he didn't new what I was talking about and got me a bit scared...

I went to the dealer two weeks ago. Told them if they could check it out as well. They looked at me and asked why and that they never heard of this problem on pathfinders. On the sentra, yes but not the trucks. then the concluded to tell me it would take 4.5 to 5 hours and cost around 400 bills. I hate stealerships. Decided not to have it done. Now I do not know what to do. Thinking of going to my friend who is a mechanic or another person that works on 350Z but he's a bit far.

This is all I have... Only a break-down of what you need to take apart to get there... We are talking about part #2 (lower manifold) right, rather than the upper. I have a damaged VQ35DE sitting in a barn out of town that I've been meaning to strip down. When I do I'll post comments regarding the tightness of these things. Anyone need parts? I'm pulling injectors and sensors etc... everything else in the metal bin at work.

Check out this post, only 2.7 hours for me: link

Thanks Trainman, I think I tread that post and told the guy it should not take longer than 3 hours. He then gets a hold of a mechanic and told me it a all day thing. Those guy are a joke.

If I recall right, my mechanic said the book time was 3 hours, so that was going to be max they were going to charge (even if took longer, I am so glad I have a shop I can trust). I suggest you try an independent shop and see what you get.

Just to make sure that I understand... The power valve are directly on the lower intake manifold (2) the valve are not individual but more like a block?

...and just for emphasis, here's a pic of one after the intake was pulled and missing parts were discovered. Creepy.