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*Updated: 02/06/2022 5:26PM PST

Threadlocker on Power Valve screws (pics)


BowTied
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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!!! :crossedwires: This protects electronics.

 

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

 

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! :nono:

 

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.

2002VQ_006.jpg

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.

2002VQ_015.jpg

 

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).

2002VQ_016.jpg

 

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

2002VQ_017.jpg

 

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

2002VQ_018.jpg

 

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

2002VQ_007.jpg

 

 

2002VQ_008.jpg

 

 

There are only 4 fasteners holding the lower intake in place - or so it would seem! :sssh: 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.....

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

2002VQ_009.jpg

 

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

2002VQ_010.jpg

2002VQ_019.jpg

 

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.

2002VQ_020.jpg

 

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........

Edited by BowTied
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I know you're not done yet, but this thread should really be pinned, or at least made a topic in the How To section.

 

GREAT walk-through here...thanks for all the info.!

Edited by navygz19
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Thanks Gianni.

...

 

But, then I notice that there are whole bunch more screws inside the intake manifold still on the bloody engine! :ohno01:

 

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

2002VQ_022.jpg

 

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.

2002VQ_011.jpg

 

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.

2002VQ_012.jpg

 

It is waaaay down inside the valve cover.

2002VQ_014.jpg

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

Edited by BowTied
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I plan on doing my plugs when I'm in there as well, as well as the PCV valve which is another cause for concern. I've got a tick under 96K on my stock plugs...they're about due for a change (105K)

Edited by navygz19
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  • 2 weeks later...

Just as a follow-up, I have a few hundred kms on the clock since the work with no problems.

 

I am wondering though if I should have done something with teh PCV while I was in there? How long do these last before maintenance in needed?

Edited by BowTied
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  • 3 months later...

I found this guidance very helpful. Thank you, BowTied :aok:

 

The entire job really isn't that bad, one just has to be methodical about a system for remembering how all those hoses and clamps get re-installed. I really liked that idea of pushing the bolts through cardboard to keep them in order.

 

I ended up taking off the resonator box under the intake hose. It really did make life a lot easier. Rotating the clamp on the box's connection to the intake helped me actually see the screw head. I used an offset ratcheting screwdriver in the tight space, though one would incur just a little more fuss with a regular screwdriver.

 

I had a bit of trouble with the weatherproof electrical connectors. The FSM has info on how to unlock them, but I couldn't get the knack of it. Sometimes it took me almost 10 minutes of fiddling before they finally came apart. My advice is to NOT force the connectors apart: when they are finally unlocked, they come apart with almost no force.

 

Before delving into this procedure, VQ35DE owners with manual transmissions should read this post and check if they have any power valves at all. Although you might not have power valves, there are still the swirl valves which you definitely have. So I'd still keep an eye on this topic in case it's determined they have the same problem.

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I found this guidance very helpful. Thank you, BowTied :aok:

 

Thanks!!! I hadn't gotten a lot of response to this post, thought maybe I had made too small or too big of a post. Glad it helped someone!

 

Thanks for info on the MT trans engines, great info.

Edited by BowTied
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Thanks!!! I hadn't gotten a lot of response to this post, thought maybe I had made too small or too big of a post. Glad it helped someone!

You did a great job, and I think many more people have or will use your post than you'll hear from. Any given forum will have many times more lurkers than regular posters.

 

However, I do believe it's good practice to at least send a private message to the author if I found a HowTo useful. A pat on the back will also make the author more inclined to share in the future. Even a simple "Thanks, Dude! You da man!" private message can make a big difference for the entire forum ecology! ;)

Edited by IncidentalOffroader
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  • 2 weeks later...

Although I do not own a VQ, I must must say that posts like this one are the exact reason I join forums.

BowTied, thank you so much for the time you took in order to post this.

I'm sure that you're helping more people than you'll ever know.

Mebers like yourself make this forum so awesome.

BIG THANKS AGAIN!!!

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  • 8 months later...
  • 1 month later...

Hey Bowtied,

 

Just wanted to offer my thanks on an excellent guide. I wouldn't have attempted this fix without your guide.

 

Couple of comments (I have an '03 SE Auto 4x4 with 75k miles):

 

1) My power valve screws were in tight and also had some gunk on them that we cleaned out prior to adding locktite. Not sure if they had been threadlocked or not at the factory, but they were not backed out of the valves at all.

 

2) My throttle body looks different than the one in your pics. On the backside of the throttle body (firewall side), there is what appears to be an electronic control module and there is no linkage on the frontside. Any idea what changes occurred between the '02 and '03?

 

3) I replaced my PCV valve while I had the manifolds off. The PCV valve in my engine (probably OEM) is threaded into the valve cover. If you search on rockauto.com (or another parts website), two types of PCV valves come up. One, the Fram version, just seems to plug in and is not threaded. This part did not look like the one that came out of my engine. The second type is threaded and costs 3-4x as much. However, there seem to be different versions of threaded PCV valve. The ACDelco variety does not fit. Any idea why different valves are showing up for the same engine?

 

Again, thanks for a great post.

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Hey Bowtied,

 

Just wanted to offer my thanks on an excellent guide. I wouldn't have attempted this fix without your guide.

 

You are very kind to say so! Glad I could help, I get a lot from the on-line community, it feels good to give back once in a while.

 

1) My power valve screws were in tight and also had some gunk on them that we cleaned out prior to adding locktite. Not sure if they had been threadlocked or not at the factory, but they were not backed out of the valves at all.

 

2) My throttle body looks different than the one in your pics. On the backside of the throttle body (firewall side), there is what appears to be an electronic control module and there is no linkage on the frontside. Any idea what changes occurred between the '02 and '03?

 

3) I replaced my PCV valve while I had the manifolds off. The PCV valve in my engine (probably OEM) is threaded into the valve cover. If you search on rockauto.com (or another parts website), two types of PCV valves come up. One, the Fram version, just seems to plug in and is not threaded. This part did not look like the one that came out of my engine. The second type is threaded and costs 3-4x as much. However, there seem to be different versions of threaded PCV valve. The ACDelco variety does not fit. Any idea why different valves are showing up for the same engine?

 

Again, thanks for a great post.

 

 

1) Where they tight as in you had to break them free (you hear them crack loose)? If so, then yours were different than mine which were not loose per se, but required little effort to start to loosen.

 

2) I am not sure? So, you have no cables at all like I do? I wonder if your throttle is a drive by wire system... is the throttle touchy? I test drove an 03 chilkoot before buying my 02 and noticed the throttle was touchy (hit hard with light pedla perssure) compared to other cars I have owned.

 

3) Sorry, I really have no idea. This is a good question to post in the R50 forum.

Edited by BowTied
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1) Mine were definitely tight - they did feel like they cracked lose. (I slightly stripped the first screw when backing it out because I assumed it would be loose and didn't apply enough pressure. The others did not strip as I applied more force on the screwdriver to loosen them.)

2) Yes, I believe the '03s have a drive by wire system, although I guess I assumed all the R50's with the VQ35DE had electronic throttle control. The throttle is fairly touchy such that when I first had the PF, I often started a little quicker than I would have liked. As with all things like this, you get used to how much pressure is required.

3) I'll post to the wider community and see if anyone has some ideas.

 

Thanks again,

Bryan

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  • 8 months later...

So I have 90k on my 01 LE. I believe that I have heard somewhere that pathys with that many miles rarely have a screw fall out. *knocks on wood* That being said I would still like to do it someday, but im really hesitant to do it myself- Im bound to screw something up....i guess the best way is to pay a shop to do it, and just ask for all the old gaskets back to make sure they actually did the job, and didnt just take the money since there is no real way to check :(

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  • 4 months later...

So I have 90k on my 01 LE. I believe that I have heard somewhere that pathys with that many miles rarely have a screw fall out. *knocks on wood* That being said I would still like to do it someday, but im really hesitant to do it myself- Im bound to screw something up....i guess the best way is to pay a shop to do it, and just ask for all the old gaskets back to make sure they actually did the job, and didnt just take the money since there is no real way to check sad.gif

 

 

I somehow missed your post, sorry. The job is really more time consuming that hard. It is simply a series of unbolt and bolt it back up. But I realize comfort level varies with engines. If you decide to tackle it yourself, just write down each step as you go and keep good track of all the fasteners. It would be my opinion that a competent dealer could perform this task in about 2 hours. Joe average garage, maybe 3 hours. That should give you an idea of labour charges.

 

Yours might be fine as is as there is only a small percentage of them experiencing failure. You will never know until you do the maintenance or it is too late. So, it is one of those Clint Eastwood moments: "...you've got to ask yourself one question: Do I feel lucky? Well, do ya, punk?" :D

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  • 5 months later...

Wish I had found this post in a pro-active fashion rather than a re-active fashion. 3 of 6 butterflys came completely off and one screw was missing on a 4th on my 115000km 04. Sadly I am having a 123000km junk yard engine put in but will have the screws locktited first.

 

Has anyone tried peaning the ends of the screws?

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  • 1 month later...

Hey all , New here , And just wondering is it necessary to also do the swirl valve screws or just the Power valves screws with loctite ...

 

If I only do the power valve screws am I short changing myself ..???

 

Also does anyone know the torques specs for the Intake ...i would think that would be important ..

Edited by Litey
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just the power valve screws

make them snug

 

O.k. just wanted to say that this past weekend my good bud and I dove in ... we removed only the upper plenum and found very tight

screws on my 04 LE . But we did our own Loctite blue on each one and put them back .

I respect Bow Tied for his painstaking detail , but feel there were many ways to go around things to get to the screws .

First we did not remove the Throttle body from the upper plenum ....rather left it attached and the coolant lines attached to it and merely just tilted the whole unit resting on the Throttle Body( TB) up in the air on the opposite side of the TB. We did remove the entire airbox previous

to this by just disconnecting everything except that lower box and just jimmied it out of the place being careful not to get hooked on any wires or hoses . This saved lots of time ... we were done in less than 2 hours and even took a break to talk to some relatives that visted .

We did use the torque specs from the FSM ... and used there tightening sequence .... but didn't replace any of the 2 gaskets from the Plenum housing ... but did use spray tack ...aerosol gasket seal ... on the old used gaskets which were very metallic or metalwrapped and in pristine condition ... I was am not trying to be cheap , and had purchased them but did not remove them from the box after considering how god they were when they came off .

 

Anyway take your time and realize their seems to be a lot to remove ...but it was not a hard job .

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Hey Tungsten Thanks ,

 

But since new to Patherfinder ownership , can you or anyone link me to the ignition system issues and fixes so I can have like you say ,

a long running engine .. Thanks and sorry to have to ask ... I am searching as well ...

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  • 11 months later...

Bump!

 

I'll be going down under the lower intake manifold this time to swap out the PCV valve... annoying cost to eat in gaskets and the valve itself (about $68 total?), not to mention the time wasted to access the damn thing. My local dealer somehow had all the gaskets I needed plus a rubber grommet thing that goes around the PCV, but not the valve itself, so I'm waiting on that. I'll probably tackle it this weekend. Does anybody want pictures of anything specific while I have it all disassembled? I'd say the original post has it down damn good. I'll list the part numbers for all the gaskets & PCV valve I got from the dealer later. I'll definitely report how my power valve screws look, but it's only been a bit less than two months (did them on August 2nd, 2011) and about 1,500 miles since I put red threadlocker on them.

Edited by Towncivilian
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