Power Valve Screws Falling Out On 3.5's, 01-04

[fleurys]

It is true, if you want peace of mind you can have him check it, but I have seen a couple sources that have removed the intake manifold and saw no power valve screws on their 5 speed

 

Excuse my ignorance, but I always tought that a pathfinder with a 3.5 manual or automatique has the same basic engine. I understand that the power rating is different on both and always tought it was either the cams that were more tuned for HP instead of torque or then a change in the intake runner.... BUt if the manual have no power valves screws, then how do the butterfly (round peice of metal) is attached to the rod in the intake then ??

[laxman0324]

There is no power valve, so no screws...

[BowTied]

Excuse my ignorance, but I always tought that a pathfinder with a 3.5 manual or automatique has the same basic engine. I understand that the power rating is different on both and always tought it was either the cams that were more tuned for HP instead of torque or then a change in the intake runner.... BUt if the manual have no power valves screws, then how do the butterfly (round peice of metal) is attached to the rod in the intake then ??

 

 

http://www.nissanpathfinders.net/forum/index.php?showtopic=18310

[fleurys]

http://www.nissanpathfinders.net/forum/index.php?showtopic=18310

 

 

ok now i feel dumb. ..thanks for the feeling ....i guess i'll have to better keep track of the threads out there...

[BowTied]

No biggy

[LovemyPathfinder]

i heard this doesnt apply to manual tranny equiped vq pathfinders? Is that true? There are no power valves. Is that true?

[LovemyPathfinder]

^^^ ok nvm! i got it. Thx for the link. SWEET!!!

[Kingman]

i heard this doesnt apply to manual tranny equiped vq pathfinders? Is that true? There are no power valves. Is that true?

 

http://www.nissanpathfinders.net/forum/index.php?showtopic=18310

 

As seen above.

[jimmycapp]

I got fskced. Driving this morning and the engine started knocking. Pulled over, had AAA tow home. pulled off the upper intake. 2nd from the fire wall valve was on top of 1st valve. two screws missing. Found one of them on top of a valve. Used a magnet to get it out. Put it back together and it still sounds like @!*%. What/where do these screw cause the failure?

 

This @!*% pisses me off.

Edited June 7, 2009 by jimmycapp

[vanuatoo]

This is really annoying issue.

 

I own 2003 pathfinder with 50,000 miles on it.

I don't live in USA and don't want some self-taught technician to touch my engine.

 

I wonder what is the statistics, I mean how random is the issue. On what mileage does it happen, what VIN codes?

It does not seem to be an engine defect, just the assembly issue.

 

Does anyone know if those screws are tightened by hand work or robot?

 

I really feel like playing a lottery just will be happy not to win a prize.

Edited June 9, 2009 by vanuatoo

[BowTied]

What/where do these screw cause the failure?

 

 

Sorry to hear that man. When the screw falls into the engine it can get sucked right into the combustion chamber where it could score piston, cylinder walls, damage valves. It will bounce around in there until, maybe, it goes into the exhaust and into the cat.

[Issac]

I joined this site to add to the list of people screwed over by the power valve screws.

The butterflys cannot make it in to the engine btw, so its screws only. The are not brass also-They are magnetic. I don't believe Nissan when they say this problem is rare. If everyone with high oil consumption looked at the screws, they might find the answer. Fuel consumption and valve damage are hints for sure.

My butterflys ended up in the #6 location, sandwiched on each other and yet they came from 3 and 4 locations. So what this means is they don't go down directly when they fall out. If your missing your butterflys, look in all the locations. So the valves might not be where you think. My valves looked much like the picture earlier in this topic, and it was the person who lost 3 I believe. My truck was well taken care of, but this has done who knows how much damage.

The screws are Not soft, so don't think they pass gently....more like a kidney stone. 2 full days work hunting and removing.

The Swirl valves look suspect too. To get to all this your going to pull a lot of mounts and little bolts. No special tools required, but a couple were a little tricky.

I would not be intimidated by this as a Pro mechanic only type thing, but its not easy. Plan more time than you hear people saying to do it right. If you have all your valves thank your lucky stars. Don't just loctite, flare the ends or otherwise.

Thanks to Bow Tied and others for the help.

Edited June 14, 2009 by Issac

[vanuatoo]

I joined to add to the list of people screwed over by the power valve screws. The butterflys cannot make it in to the engine btw, so its screws only. The are not brass also-They are magnetic. I don't believe Nissan when they say this problem is rare. If everyone with high oil consumption looked at the screws, they might find the answer. Fuel consumption and valve damage are hints for sure. My butterflys ended up in the #6 location, sandwiched on eachother. So what this means is they don't go down directly when they fall out. My missing valves were the middle 2. So the valves might not be where you think. my valves look much like the picture in this topic of the person who lost 3 I believe. My truck was perfectly taken care of, but this has done untold damage. The screws are Not soft, so don't think they pass gently....more like a kidney stone. Nissan lost me as a customer. 2 full days work hunting and removing.

The Swirl valves look suspect too. Its the plenum upper and lower, and the manifold to get to much of it. Plan more time than you hear people saying to do it right. If you have all your valves thank your lucky stars. Don't just loctite, flare the ends or otherwise.

Thanks to the person who showed pics on how to.

Really sad to hear that. What is your car mileage?

[Issac]

Really sad to hear that. What is your car mileage?

 

HI I am working on it now so am kinda right up to date on the whole thing. My truck is 115k miles and well serviced etc. I am a Pathfinder lover and currently am kinda mad at Nissan but will get over it.

The whole power valve (butterfly really) issue is pretty scary as far as engines go. The screws are not soft as stated elsewhere, and to be honest it seems like a little bit of a crap shoot if you get damage or not.

My truck was getting bad mileage and it use to get very good compared to others. There was also a vibration at 3400 rpm that I never tracked down. After doing all the standard stuff of shields and plugs and ujoints etc., now I think I found that. It was likely these 2 butterflys sitting on each other flat in the back location of the manifold.

There is no way for these Butterfly power valves to travel past the Swirl Valves, but... mine had vibrated long enough to lose the finish to a silver color from gold on one side where they rubbed eachother, and 5 screws are MIA.

 

So it all happened and one day things were find and all I knew was not so good mileage and the truck doesn't burn oil or anything unusual.

 

Then a couple days ago..."clack clack clack" just like Lifters but louder. I shut it down immed. Stuck lifters? Cam bearings? Didn't know. What the heck was that?

 

But I knew my engine was real clean so that made lifters a little unusual of a problem. Still I needed to check the cams/lifters and who knows what else, and they were all fine.

Then it hit me....Power Valve. I knew it instantly. That was the thing I had heard about when I first started reading up. Kinda forgotten infact.

 

See, I was quite sure it has been done already (paperwork from the last repair). In fact it was done by the dealer. But regardless this was previous owner, and my mistake was having someone else do work and I took this as being ok. It was not!

 

After taking this stuff apart i figured out that a while back the Butterflys had come loose and fell in, and what I heard was the 5th screw landing in my piston top a couple days ago. Meaning, the 3rd failed powervalve is/was hanging by one screw.

So the wonderful help Bowtied put on the original post was a great place to start, But I had mine already fail and needed to go further.

The repair is not real bad as far as requiring skill, but if you think its a couple hours your mistaken. Simply cleaning the plenum and intake and gasket surfaces properly and letting loctite dry and aligning butterflys (a simple tooth pick tip works fine when you compare that to screws falling in and blockage down stream) takes longer than that and there are many things you can do on the way.

Bad news is Nissan doesn't sell the Power Valves as far as I could find, and they want $350 for the plenum portion- um for your mistake?

I did some other things while I was there and like BowTied said, the plugs. Also if you lost screws, likely your plugs are hammered-literally, so its NGK plat time, and more $.

So this engine had a screw in it when I shut it down.

Then I put a huge shopvac directly on the Intake Manifold (below plenum) with the spark plug out and sucked the heck out of it...and then on the plug hole.... and all the while I did this, I gently turned the crank (engine over) with a socket (buddy needed).

Junk came out but it likely was around the general area and I can't be sure either way sadly. It was kinda shade tree but I don't care.

So then I connected battery, and cranked the starter with no compression and the sucker turns real fast that way. During this process I had the shop vac again.

Of course the engine can't start so thats no big deal. the engine was silent. I tested more...and more....zero screw sound.

So I wonder now if the screw was there and had passed, Or it was the butterflys smacking on eachother, or the screw passed...either way, this is good news.

Now I am using NEW gaskets, and they were only $36 at Autozone. i wouldn't want to have leaks here.

So its clean all threads of bolts and retorque...

Hate to say it but as far as I can tell there is nothing you can do about this other than doing it .Do it yourself and save and learn a bit like I did.

I don't recommend or claim to be an expert in anything I did, just my story.

By the way, I put in Allen high grade black screws with 1mm more of thread. While this might be a no no, I then had a little extra thread to disfigure to keep the screw if worst case it doesn't hold. Whoever said Red loctite I totally agree. Why removable? Shoot I almost thought of JB weld also. Remeber, Locktite is only as good as you prep threads and have them oil free. Also new screws are going to be tighter fit than old vibrated screws.

Good news is you can clean your plenum and get all the junk out. I went thru 2 cans of carb and lots of nasty fumes to get it clean.

Going into this my process was longer than most because I didn't expect this could happen. But either way, I am no mechanic, but I can do most average repairs no problem. So don't be scared, take pictures as you go, and clean clean. This is a job a owner can do.

In the end I had only ONE butterfly that the bolts were snug and correct- out of 6. None were close to snap tight.

I used allen /hex (2mm) pan head bolts.

If you have an auto of this problem generation I would do it. Your looking at a day if the screws have not fallen. If you have a trust mechanic who doesn't have a lot of Nissan experience, they can do this. It seems to me to be straight forward repair, just explain the issue.

Keep stuff organized and your work area clean. Its mostly 10mm socket and 12mm and piers and grease rags. I found a shop vac handy because you don;t want stuff falling in. Stuffing something to plug intakes as you clean and work is good also. If you want to do your valve cover gaskets this is not a bad time also. If you put plugs in some antiseize and dialectic grease on the coil packs works wonders for removal. Clean the valve cover top for a good seal before you plug these back in.

Make sure everything is numbered so you can put it back in its place.

I was glad to have BowTieds early work on this and can't thank you enough. In the end most repair shops could really rip you off or half ass the prep work on install and removal. Get some wire and plastic brushes too.

If the screw was still in there, it gets very serious because this becomes a major task at that point.

Ounce of Prevention thing. Get a day and go for it. Second time a person does it is easy! Hopefully none of us.

The whole vacuume techinque I came up with might sound desperate, but hey you wanna pull heads and try to make room in there to do so? Not me. Well there was clatter when I shut it off, then when i crank it now, nada. I never did find the bolt and who knows?

Sorry for the long post, the reason is I would have liked more info if I had done it, so I added what I could.

Edited June 14, 2009 by Issac

[jimmycapp]

Your lucky. Not so much on mine. I pulled my motor yesterday. What a pain in the ass.

[CDNBullrid]

just checked all my butterfly valves when i did timing chain. all were tight. removed and put heavy duty loctite on the threads and reinstalled them. not a big job to do. people, if you havent done this yet, do it. doesnt take long and the 2 posts above this prove that it is worth doing.

[parrish]

Thanks to everyone involved with this thread- I just tore apart my 2001 SE this morning to check the power valve screws. Three of the valves (all towards the back of the engine) were loose- the furthest back being so loose that I could remove the screws by hand. Fortunately none of the screws had come entirely loose- so no engine damage done. But it woudln't have been too much longer and at least one or two screws would have dropped. I used red threadlocker on all the screws.

 

It appears, at least on my Pathy, that the thread locker Nissan used was the type that would deteriorate in the presence of heat. The front most screws still had some type of threadlocker on them- but it crumbled to near nothing as I took the screws out (appeared totaly dried out). I'm thinking the rear most screws may get more heat- which could explain why those screws were much looser.

 

I've got 159,000 miles on my Pathfinder- guess I should just count myself EXTREMELY fortunate that no screws fell in that time! While I was in there I decided to clean up the upper plenum (I only removed the upper to do the loc'titing- no need to remove the lower plenum as long as you are careful and use a magnetic screwdriver to capture the screws as you remove them). I also used my air grinder to smooth and slightly enlarge the opening of the throttle body mount on the upper plenum. It still had excess casting from the factory that needed to be cleaned up. Besides, the opening was slightly smaller than the gasket opening so I opened it up to match the gasket. Not sure if it will help or not- but it was a 10 minute job so might as well.

 

All told it took me just under 2 hours to complete the job. Would have been more like 1.5 hours if I didn't do the clean up work on the upper plenum. Easy job that is WELL worth it!

[carkey83]

I recently had, while driving, a ten second (or so) period of loud engine rattling and misfire. It cleared up quickly and has been fine for a week. Thinking I had a loss of oil pressure or plugged passage, I pulled the lower oil pan only to find it perfectly clean and no clues. I remembered this issue with the screws and pulled the plenum. I found 2 VIAS plates completely missing and several more screws loose. I know the plates aren't usually ingested, but they are GONE. I didn't believe this, so I popped the spark plugs out and ran a bore scope to find many plate shaped indentations on the pistons (#3 and #4.) Well, I removed the remaining plates and threw it all back together. Now, has anyone else experienced this? I have no idea how the plates made it through. It seems impossible, but I swear to you they were chewed up and spit out. I painstakingly inspected the rest of the plenum, lower intake, and any other areas the plates could have ended up. And the damgage to the pistons speaks for itself. Oh, and the engine runs perfectly with no unusual noises (for 150k + miles.) Although I can't say for how long. Just another story for the pile I suppose...

Edited January 22, 2010 by carkey83

[fleurys]

Wow....If your engine still works ok and does not start taking more oil, you might just be the most lucky pathfinder owner on this site.... I might just make you a sticker that says : "My plates are gone, Still going strong !"

[carkey83]

Wow....If your engine still works ok and does not start taking more oil, you might just be the most lucky pathfinder owner on this site.... I might just make you a sticker that says : "My plates are gone, Still going strong !"

 

I would definately rock that sticker! I still cant get over how the plates fit through the valve openings...They had to have broken up in the manifold and then gone through. And they're steel, so I cant say how long the motor is going to "go strong", but I intend to find out!

[carkey83]

I may have spoken too soon. Definately picked up some piston slap or a rod knock...any used VQ's available?

[BowTied]

Sorry to hear of the bad luck.

 

I am very surprised to hear that plates when through ... I didn't figure they'd get through the swirl valves, let alone the cylinder valves. Did you remove the lower intake plenum and view the swirl valves? They could be caught up there. The screws would leave a lot of marks on the pistons etc. Keep an eye on your oil consumption. You might just want to trade it in.

 

 

[carkey83]

Sorry to hear of the bad luck.

 

I am very surprised to hear that plates when through ... I didn't figure they'd get through the swirl valves, let alone the cylinder valves. Did you remove the lower intake plenum and view the swirl valves? They could be caught up there. The screws would leave a lot of marks on the pistons etc. Keep an eye on your oil consumption. You might just want to trade it in.

 

 

It's weird, but the plates are just plain not in there, not around the swirl valves or intake valves either. I dont know how they could have gotten through. I got the path at 98k mi, so they may have been removed before and I just heard a screw going through? But why leave the other 4 plates on... Questions that have no answers I suppose. Still running, with a light knock though. I'm taking this VQ to it's grave so lets start the counter!

[AROYK]

So I went to the dealer to see if they would do the power valve screws for me, and at first they said no because they've never heard of it, but then called me back like a week later and said,"Oh yeah, that problem! We've got a guy that's done a bunch of those". They quoted me $387.19, which I guess isn't that bad considering I don't have time to do it myself, but then I asked if they could change out the right hand valve cover while they're in there (maybe fix my oil consumption problem), and they wanted like $400 for the part. Crazy! So I ordered one from nissanpartswarehouse.com for $188 and they said that it might not get to me for a while because THIS PART IS ON NATIONAL BACK ORDER! Nobody has this part??? I find that hard to believe. Anyone else run in to this problem?

[carkey83]

So I went to the dealer to see if they would do the power valve screws for me, and at first they said no because they've never heard of it, but then called me back like a week later and said,"Oh yeah, that problem! We've got a guy that's done a bunch of those". They quoted me $387.19, which I guess isn't that bad considering I don't have time to do it myself, but then I asked if they could change out the right hand valve cover while they're in there (maybe fix my oil consumption problem), and they wanted like $400 for the part. Crazy! So I ordered one from nissanpartswarehouse.com for $188 and they said that it might not get to me for a while because THIS PART IS ON NATIONAL BACK ORDER! Nobody has this part??? I find that hard to believe. Anyone else run in to this problem?

 

If you're in Balston Spa, I used to work at the local Nissan dealer. Good bunch of guys if you ask me. I turned them on to the power valve problem after mine fell out so they should be up to date by now. Honsetly it's not a common sighting at the dealer, as the older cars usually end up at independent shops. If you decide to go back tell Larry that Vinnie sent you and he should take care of you.