DIY: Threadlocker On Power Valve Screws

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KoukiS14
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DIY: Threadlocker On Power Valve Screws

Postby KoukiS14 » Mon Jan 07, 2008 3:50 am

There is a potential issue where no threadlocker was applied to the power valve screws during assembly; this is not a very widespread issue, however. The lack of threadlocker allows the possibility of the very small screws to back out of their screw holes due to vibration, and get eventually sucked in by the engine when the power valves are actuated, potentially causing significant engine damage. It is not known which specific VINs or years are affected. Applying red threadlocker to the 12 power valve screws is a way to ensure this does not occur. This is a DIY guide on applying threadlocker to the power valve screws. If you prefer the dealer to perform this procedure, it will cost somewhere in the range of $300.

NOTE: The original thread is the property of BowTied from nissanpathfinders.net/forum. The exact content and pictures are borrowed from that site, and are re-hosted. The original thread can be found here: http://www.nissanpathfinders.net/forum/ ... opic=17104

Hi all:

I have take the engine apart on my pathy to add the loctite to the power valve screws to avoid them getting sucked into the engine.

A HUGE thank-you to my buddy Steve - without his experience from working on his Maxima and his help, I'd likely still have my finger stuck in a swirl valve....A BIG - thank-you to all who posted about this issue to alert those of us not in the know....

Note to Mods: I /IMG tagged my pics from photobucket. If someone wants to upload and modify my post for posterity, cool. Can't guarantee my photobucket account forever of course...

Details
'02 Pathy LE
111,000km (~69,000 miles)

Gaskets (4) ordered from dealer
  • 16175-4w000 (throttle body)
  • 14033-4w000 (right side, between upper and lower intake plenum also called 14010A*)
  • 14033-4w010 (left side, between upper and lower intake plenum also called 14010AA*)
  • 14033-4w00A replaces 14032-4 (between lower intake plenum and intake manifold also called 14040E*)
* (part numbers as shown on exploded view in the print-out given to me by dealership, dunno why they don't match the p/n on the packages... all gaskets fit perfect.)

These cost me approx $72 CAN as the Nissan dealer cut me some slack on the tax. The last gasket is the most expensive, almost $50. If you were going to leave the lower intake plenum on the engine to do this job, you would not need this gasket. I personally think it worth while to remove the lower plenum, makes life easier, only 4 screws hold it on, no dropped screws inside the engine.. up to you though. Some people think that these gaskets can be re-used and you do not need new ones at all - probably true, but with my luck, I decided not to do it twice for $70 and got new ones.

The following is my rough account of how I did the job, not every step is in here, but should give an overview. If you are a real noob to auto mechanics, this may be more involved than you want to try. Much harder than an oil change. Not nearly as hard as changing a transmission or even a clutch though. If an oil change is a 1 out of 10, and an engine rebuild is a 10 out of 10, this job is a 4 in my opinion.

Quick Notes:
Left and Right - refer to the side of the vehicle, so when I say left, I mean from the driver's perspective - just to be clear.I did not cut any factory tie straps!! They unclip from underneath if you squeeze the tabs together and then you can pop them back in later.

Disconnect battery negative cable!!! This protects electronics.

Remove plastic engine cover (2 nuts and a screw). Look in awe at all the bloody wires and hoses.

Remove the *mounting bracket* for the accelerator cable and what I guess is the cable from the cruise to that go to the throttle body. I did not remove the the lock nuts at the cable end, just the mounting bracket (2 screws). Unclip the the cables from the plastic clips at the front of the engine. There should now be enough slack in the cable to move them toward the throttle body - the cable ends slide to the side out of the half round throttle body mounting points. Then flip the cable assy upside down and backward toward the battery - DO NOT kink these!

Remove the brake vacuum line from the rear centre of the upper intake plenum.

Remove the hose leading away from the evap valve on the upper intake plenum near the throttle body.

Then remove the air intake hose. There is one mounting screw on the resonator box down low (in the following pic, the mounting point is visible just below and to the side of the master cylinder) to remove, plus 2 band clamps and a couple of hoses.

Image

This thing will be hard to get out, you will need to remove the hose from the throttle body end first and the twist and contort it out - watch the plastic box underneath doesn't get hung up stuff (it will). I did not remove the airbox. This would make life easier I bet, but I felt I could get by without the extra step.

Then remove the hoses around the power valve vacuum actuator at the front left of the upper intake plenum.

There are two brackets on the right side, rear of the upper intake, that are bolted to the lower intake (one has the mounting screw for the plastic cover). That one should be loosened and pulled back. They both need to come loose, so might as well do em both now.

Image

Unclip the two tie straps for the evap control valve @ back of throttle body. Disconnect two connectors at throttle body (throttle position switch and idle air control valve, brown is on top, but I think there is only one way to reconnect). I did not disconnect the coolant lines to the throttle body. I removed the 4 mounting bolts (hex key on a socket extension works best).

Image

and used some wire tied it off out of the way to the dip stick.

Image

Using the reverse of the torque tightening sequence from your manual, remove the 13 fasteners from the upper intake plenum, and them remove it. Carefull, it could get hung up on stuff. Put the bolts in a card a number them

Image

as they are different lengths and need to go back in the same spot!

Image

Image

There are only 4 fasteners holding the lower intake in place - or so it would seem! There is secretly a hidden bracket on the right side back, between the firewall and the lower plenum. The right most bolt will require a short 12mm wrench to get at it. This was the hardest fastener to deal with. Then the the 4 main fastners can be removed in reverse tightening sequence order.

Will continue in a reply post.....


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Re: Threadlocker on Power Valve screws (KoukiS14)

Postby KoukiS14 » Mon Jan 07, 2008 3:51 am

I did not remove the vacuum actuator itself as shown in this picture.

Image

The hose system underneath at the back disconnected earlier (shown now to help understand where to disconnect in the earlier step).

Image

Image

Ok, so now everything is apart. I clean the power valve area with some carb cleaner and blow it off with compressed air.

Then I remove ONE screw (to make life easy for lining up things up for assembly) and drop it in some carb cleaner and liberally blow some carb cleaner in the threads of teh mounting shaft.

Looking at the screw, it has some gunk in the threads. I need an easy way to remove the crud from these fine threads, so I got a small wire brush from a dremel rotary tool set and put it in my drill, in the vice. The screws have a round head and holding just the head with pliers is likely to launch them across the room, so put pliers on them top and bottom of the screw, seemed to work well enough.

Image

I then blow out the threaded hole with compressed air, and ad a drop of loc-tite 242 (blue removalbe for 1/4" and larger, not so easy to remove on smaller screws, may require heat!) and reassemble. Repeat 11 more times.

Use compressed air to blow any crud out of the plenum runners.

Clean all the gasket mounting surfaces with a clean rag and carb cleaner or similar.

Installation is reverse of assembly....

BUT........

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Re: Threadlocker on Power Valve screws (KoukiS14)

Postby KoukiS14 » Mon Jan 07, 2008 3:56 am

But, then I notice that there are whole bunch more screws inside the intake manifold still on the bloody engine!

I had done the power valves, but the valves underneath those are the swirl valves. ugh.

I did not have the gaskets to remove the manifold and there was no way you could or would want to do the screws with it on the engine. Plus you'd have to mess with fuel lines. So, I did something that may have no effect at all, but thought it was worth a shot:

I got an old toothbrush and sprayed it with carb cleaner liberally. My buddy Steve held the valves open with a soft handle of a hammer

Image

and I brushed the back side of the screws with carb cleaner and dried them with compressed air. I then put some blue loctite on the tip of a small clean flat blade screw driver and carefully dabbed it on the backside of the screws.

Image

Maybe that will all wash off, likley. but it is better than nothing in my mind.

Oh - one other thing, changing plugs is easy when you are this far apart, I recommend it!Just remove the coil, one bolt, and then you have access to the plug.

Image

It is waaaay down inside the valve cover.

Image

The book calls for a .043" gap. My factory plugs measured .044 after ~69k miles, so I gapped the new ones to .042 and stuck 'em in - they should be good for another 69k I hope.

Changing the plugs can be done another time, but you will be moving most of the same hoses and brackets and you will have to remove the throttle body to get to one of them, I think it is #4.

Hope y'all found this thread useful.
Ron

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Re: Threadlocker on Power Valve screws (KoukiS14)

Postby KoukiS14 » Mon Jan 07, 2008 5:38 am

Disclaimer: I hope I don't make anyone mad by stealing this info.

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Re: Threadlocker on Power Valve screws (KoukiS14)

Postby tmorgan4 » Fri Jan 18, 2008 8:00 pm

Best bet would be to send him a message on NPORA and let him know you've got it over here. After all, he did take the time to post a write-up online so other people could see and learn from it.

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Re: Threadlocker on Power Valve screws (tmorgan4)

Postby KoukiS14 » Sat Jan 19, 2008 3:08 am

tmorgan4 wrote:Best bet would be to send him a message on NPORA and let him know you've got it over here. After all, he did take the time to post a write-up online so other people could see and learn from it.
Good call. . I'll get ahold of him. .

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Re: Threadlocker on Power Valve screws (KoukiS14)

Postby timmack » Wed Mar 12, 2008 5:07 pm

rut roh, the pics are gone

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Re: Threadlocker on Power Valve screws (KoukiS14)

Postby KoukiS14 » Thu Mar 13, 2008 2:47 am

ohhh crap that's right. I'll rehost them when I get home.My ISP was sold to Comcast, and so far I hate them.1) I can't even so much as ping my IP, so no remote desktop (I'm using logmein from NC right now)2) They offered no warning before deleting my crap3) They went ahead and bumped the price up after I had signed a contract


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Re: Threadlocker on Power Valve screws (KoukiS14)

Postby c_law23 » Sat Apr 12, 2008 5:59 pm

any luck with them pics?

Thanks

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Re: Threadlocker on Power Valve screws (c_law23)

Postby KoukiS14 » Fri Apr 25, 2008 3:53 am

Wow that's screwed up...I come back here to finally fix these pics...And uh. . Comcast decided to let me have my FTP access back. (Comcast recently bought out Insight locally).

Well sheeeeeeeeeeeit. . .

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Re: Threadlocker on Power Valve screws (KoukiS14)

Postby car-parts-happy » Mon May 19, 2008 7:36 am

Hey - cheers for the guide, but I still can't see the part pics? They back up?

EDIT!Just re-freshed! Oops. I'll take a good look at the guide later - could be useful with my latest project

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Re: Threadlocker on Power Valve screws (car-parts-happy)

Postby KoukiS14 » Mon May 19, 2008 1:04 pm

car-parts-happy wrote:Hey - cheers for the guide, but I still can't see the part pics? They back up?

EDIT!Just re-freshed! Oops. I'll take a good look at the guide later - could be useful with my latest project
Hope it works out for ya, otherwise I stole it from that dude for no reason. . haha

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Re: Threadlocker on Power Valve screws (KoukiS14)

Postby pathfinder9035 » Mon Dec 01, 2008 10:08 am

ok...does this apply for 01 pathfinders!?? with 5 speed manual.. pls answer soon .

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Re: Threadlocker on Power Valve screws (pathfinder9035)

Postby timmack » Fri Dec 05, 2008 3:21 am

im pretty sure it applies to all pathfinders/qx4's from 00-04 with the 3.5.

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Re: Threadlocker on Power Valve screws (timmack)

Postby KoukiS14 » Sat Dec 06, 2008 6:26 am

Already said. . but sure does. AFAIK, any R50 with VQ.

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Re: Threadlocker on Power Valve screws (KoukiS14)

Postby Bow_Tied » Tue Jan 27, 2009 8:14 am

Hi all,

No need to contact me for permission to use the photos, I found you first!

Just kidding... I am happy to have the pics here - I want everyone to be aware of this issue and avoid problems, same way I benefit from others' How To posts. So keep this post here! Small caution, I am not promising to keep my photobucket account forever, so if you want to d/l a rehost those photos here, you have my blessing. I do appreciate the credit for the initial write-up. Anyone wishing to add/update/correct info along the way has my blessing too.

Side note, from what I have gathered this does NOT apply to 5 speed manual rigs. From what others at NPORA have posted the manual trans equipped rigs do not have thses valves at all.

Hope that helps! Ron

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Re: Threadlocker on Power Valve screws (Bow_Tied)

Postby sobiloff » Fri Mar 20, 2009 10:05 am

My 2002 QX4 has been down on power for for about six months and I've been going crazy trying to figure out what the problem is. My last used oil analysis showed a sudden spike in chromium, meaning something wasn't happy in a cylinder. My oil guru thought it could be a broken ring, a cracked piston, or possibly a bit of debris from a disintegrating cat getting sucked back into the cylinder. No engine codes are being thrown, though, and there's no oil consumption, either. So, I took the truck to the dealer and asked them to check the cats, but they both turned out to be in good shape.

Then I found this thread.

So, I asked the dealer to check the power valves and they just called with the verdict: one screw gone and the loose valve was binding the entire assembly, restricting airflow into the engine.

While I'm happy that I've finally tracked down the problem, I'm frustrated that this has happened to my engine. I've asked the dealer to see if they can get some consideration from Nissan/Infiniti since this clearly is a quality failure and not the result of wear or abuse. I know I'm out of the warranty by both time and mileage (69K miles on the truck now), but I hope that they'll help offset the cost a little. (I haven't gotten the final bill, but I'm probably looking at $600 for the work.)

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Re: Threadlocker on Power Valve screws (sobiloff)

Postby montrose michael » Wed Apr 08, 2009 7:59 am

Hi All, I'm new at this ... signed up today as as result of a problem with my 04 Path 4wd Platinum. Coming down the exit ramp after a fine ride from Paso Robles, I heard a loud clatter that wasn't Santa on my roof of course. Long story short, 2 weeks of back and forth with my mechanic, engine flush to release "locked up" hydro lifters, followed by a suggested $2,600 removal of the heads to unplug the oil feed to the lifters, and buddies saying try more flushing, etc.... I was called over to see missing screws and one missing butterfly!!

Your notes and comments and pics by friend KoukiS14 confirm my problem and the solution by my mechanic. IT AMAZES ME THAT THIS PROBLEM IS HAPPENING. Seems an engineering issue that is a design flaw. I'm not expecting help from Nissan at 98k miles but this surely isn't the reliability I was expecting from Nissan.MM

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Re: Threadlocker on Power Valve screws (montrose michael)

Postby montrose michael » Wed Apr 08, 2009 12:10 pm

Well, all screws and butterflies accopunted for and returned to correct place with locktite. BUT, noise remains! Any guesses?

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Re: Threadlocker on Power Valve screws (montrose michael)

Postby ianh » Thu Jul 09, 2009 11:16 am

Any updates ?what did you find ??

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Re: Threadlocker on Power Valve screws (ianh)

Postby montrose michael » Mon Jul 13, 2009 12:14 pm

I finally bit the bullet and had the engine dismantled to the blok. Butterflies were replaced, screws locktighted and pened over and all re-assembled. $3,000 later (including a small discount to round it off to $3k), the truck is back on the road. Initially there remained some minor clatter when running a cold engine, but after 500 to 600 miles, all is as pre-clatter. just my pocket book is different. Maybe I'm expecting too much but I remain sceptical that something like this should not be a recall!?

Thanks for asking.

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Re: Threadlocker on Power Valve screws (montrose michael)

Postby jeffcrider » Tue Sep 01, 2009 4:27 am

Hey All,

I'm in a pickle and need some help.Just last week a screw fell out of my power valve and into the cylinder of my 04 pathfinder. (76,000 miles)

The dealership quoted me $3500 to take the screw out... but they couldn't guarantee that the engine wasn't scratched and ruined, so if they got the screw out and found the engine was scratched they would then need to replace the engine for an additional $8,000 to $12,000...

I'm thinking I get it towed back to my house and I try my best to take the heads off and take out the screw myself and trade it in when I'm done

Any thoughts on this? Is there a DIY somewhere for this?

I've already tried to get Nissan to cover it but I was denied

Not sure if this is needed info or not.But they tell me it is in the #4 cylinder (2nd one back on the passanger side looking at if from the front of the vehicle)

-Jeff
Modified by jeffcrider at 10:47 AM 9/1/2009

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Re: Threadlocker on Power Valve screws (jeffcrider)

Postby montrose michael » Tue Sep 01, 2009 8:52 am

Hey Jeff,

That seems to be the deal, plus or minus. The thread on this topic is sadly interesting and very informative. If you think you want to tackle the job yourself, scroll way to the top and you'll be able to read and see pics of a part by part repair posted, courtesy of a talented do-it-yourselfer. he gives and excellent discription and some dos and don'ts.

Good luck.

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Re: Threadlocker on Power Valve screws (montrose michael)

Postby jeffcrider » Wed Sep 02, 2009 6:58 am

Well, I did see what was posted. But my problem is more then just a preventative measure. I actually have a screw in my cylinder! there is more to be done then just putting lock tight on my screws. The dealer ship tells my I have to take the heads off my engine and look down inside and take the screw out!

BUT!!! I'm actually set (I think) I was able to borrow a borescope and look at it my self. it appears as the screw is smashed and imbedded into the piston head. The knocking sound was the screw hitting the top of the head. and now the screw has been (hopefully) permanently imbedded into the piston. there is no knocking anymore!

(I'm going to trade it in ASAP)

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Re: Threadlocker on Power Valve screws (jeffcrider)

Postby jeffcrider » Fri Sep 04, 2009 9:10 am

Wow... I'm kind of a scatter brain. I've changed my mind and i think i'm going to just keep my pathfinder....

I have one question though. Is it possible to take the upper intake plenum off the top of the engine with out removing the throttle body?It looks as though i could just un screw the intake plenum and lift it up and fix the power valve screws but not actually take the intake plenum out of my vehicle.

Reason i ask is because i want to get this done asap (today or tomorrow) but no one has the throttle body gasket... i'd have to wait till middle of next week to get the gasket.

What do you think?

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Re: Threadlocker on Power Valve screws (jeffcrider)

Postby jeffcrider » Sat Sep 05, 2009 4:17 am

Never mind... I did it last night. you don't need to take the throttle body off.

And i was mistaken on exactly where the power valves were. I thought they were on the upper plenum. they are actually on the lower. I removed the upper and was able to remove the screws and put thread locker on them and replaced them while the intake was still attached to the engine. I had no clue what i was doing and it only took about an hour to an hour and a half. it really wasn't that hard.

Thanks for the DIY!

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Re: Threadlocker on Power Valve screws (KoukiS14)

Postby Phoenix2002 » Sun Jan 31, 2010 1:47 pm

Thanks to everyone for posting this info. I just bought a 2002 Pathfinder LE last month with 75,000 miles on it. Just to be sure, I checked my power valve screws and to my dissapointment, I found one missing. Several others were loose as well. A Nissan dealer told me they don't sell the screws by themselves, but I was able to find plenty at a local hardware store. I put threadlocker on all 12 and everything seems fine now. No noise or any symptoms of problems with the lost screw before or after disassembly, so I just ignored it, since I didnt have the resources to do much about it anyway.

Question: I noticed that my hardware store also sold lock washers that would fit these screws. Would there be any advantage to putting some of them on (in addition to threadlocker) the next time I open my intake up?

Thanks again!

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Re: Threadlocker on Power Valve screws (pics)

Postby CanuckQx4 » Sat Oct 23, 2010 2:54 am

Anyway to get all the pics working again??

Id love to do this on my 3.5L qx4

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Re: Threadlocker on Power Valve screws (pics)

Postby CanuckQx4 » Tue Oct 26, 2010 12:41 pm

Just did this to my truck and glad I did!!! 2 of the screws were already backed out and ready to drop!!!! 5 of them were barely even snug, didnt take any force to spin them out

Only took an hour.. no gaskets needed to be replaced, only cost me $5 in carb cleaner

I HEAVILY suggest everyone that reads this make the time to get it done

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Re: Threadlocker on Power Valve screws (pics)

Postby funnyman82 » Fri Dec 10, 2010 5:49 am

I do not see all the pics? I really want to do this by myself.

But can I take it in to a mechanic and mention the power valve screws? They should be able to do this right?


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