DIY: Threadlocker On Power Valve Screws

A forum for the legendary Nissan Pathfinder and Infiniti QX4.
User avatar
vannaksao
Posts: 56
Joined: Mon Mar 29, 2010 2:43 pm
Car: 2003 Nissan Pathfinder SE, 1997 Mitsubishi Eclipse GSX

Post

I think I might have the same problem. Can you guys listen, and watch this video to see if you can determine if I'm one of the lucky ones to have to open up my intakes? :tisk:

<object type="application/x-shockwave-flash" width="400" height="300" data="http://www.flickr.com/apps/video/stewart.swf?v=71377" classid="clsid:D27CDB6E-AE6D-11cf-96B8-444553540000"> <param name="flashvars" value="intl_lang=en-us&photo_secret=0bc70d1e1f&photo_id=5249891796"></param> <param name="movie" value="http://www.flickr.com/apps/video/stewar ... 7"></param> <param name="bgcolor" value="#000000"></param> <param name="allowFullScreen" value="true"></param><embed type="application/x-shockwave-flash" src="http://www.flickr.com/apps/video/stewart.swf?v=71377" bgcolor="#000000" allowfullscreen="true" flashvars="intl_lang=en-us&photo_secret=0bc70d1e1f&photo_id=5249891796" height="300" width="400"></embed></object>

If the above link does not work, please use this:

http://www.flickr.com/photos/56891815@N04/5249891796/


User avatar
Towncivilian
Posts: 4995
Joined: Sun May 23, 2010 10:21 am
Car: 2001.5 Pathfinder SE 3.5L 2WD A/T
2007 Altima 2.5L CVT
2012 Sentra 2.0L CVT Special
2012 G37 Sedan 7A/T
Location: Florida, USA
Contact:

Post

I've got new gaskets (first three only, I don't plan on removing the lower intake plenum), gasket sealant, a gasket scraper, Permatex red threadlocker, and a socket set. I'll have a torque wrench soon. Is that all I'll require to do this job?

What, exactly, does this job entail? Removing engine cover, throttle body, anything else in the way (i.e. wiring/harnesses, and are there any hoses?), and the 13 bolts on the upper intake plenum, then simply removing the plenum, putting threadlocker on the power valve screws (are the power valves on the driver's side or passenger side of the engine?), and reassembly (changing gaskets where applicable)? About how long would this take for a complete newbie and an equally inexperienced friend or two to complete? I've not gone any deeper than accessing the camshaft position sensors in the engine. Short of dropping screws (I'll be sure to use magnetic tipped screwdrivers), any other potential areas for failure? What torque do I torque things to (any FSM page to list these numbers?)?

User avatar
vannaksao
Posts: 56
Joined: Mon Mar 29, 2010 2:43 pm
Car: 2003 Nissan Pathfinder SE, 1997 Mitsubishi Eclipse GSX

Post

Town, read the original thread, its very helpful. If you want to wait- I'll be opening up the beast tomorrow morning, and I'll take lots of pics. Maybe I'll even make a video out of it. I just need for someone to confirm that the sound I posted is it.

User avatar
Towncivilian
Posts: 4995
Joined: Sun May 23, 2010 10:21 am
Car: 2001.5 Pathfinder SE 3.5L 2WD A/T
2007 Altima 2.5L CVT
2012 Sentra 2.0L CVT Special
2012 G37 Sedan 7A/T
Location: Florida, USA
Contact:

Post

vannaksao wrote:Town, read the original thread, its very helpful. If you want to wait- I'll be opening up the beast tomorrow morning, and I'll take lots of pics. Maybe I'll even make a video out of it. I just need for someone to confirm that the sound I posted is it.
I'm in no rush and can wait for pictures. I'll also read the original thread at some point. Thanks for the reply.

User avatar
vannaksao
Posts: 56
Joined: Mon Mar 29, 2010 2:43 pm
Car: 2003 Nissan Pathfinder SE, 1997 Mitsubishi Eclipse GSX

Post

Hey Hey,

I inspected the noise a little more this weekend. I think the clicking might be a bad bearing in the idler pulley, alt & ps side. Took it off and the pulley makes a very faint click when I spin it. So I imagin that under belt tension, it would magnify the click making it much louder. The reason why I'm going to replace the pulley first: $30 bucks right now is worth not having to go outside in 10 degree whether, sticking my head into the engine bay for the 40th time this month. Second reason, If a power valve screw has fallen out, I don't think my engine would be running right now. I'm definitely going to trust the veterans and threadlock the screws, but not right now. I'm gonna wait until the weather gets just a little nicer, and focus on other components that need more attention.

Sorry to make you wait for nothing. PM me if you have any questions about anything. I have no problems going into the engine bay and taking pics and vids.

User avatar
Towncivilian
Posts: 4995
Joined: Sun May 23, 2010 10:21 am
Car: 2001.5 Pathfinder SE 3.5L 2WD A/T
2007 Altima 2.5L CVT
2012 Sentra 2.0L CVT Special
2012 G37 Sedan 7A/T
Location: Florida, USA
Contact:

Post

No big deal, I can wait. I did read through the giant thread @ NPORA and the job doesn't seem to be that big of a deal, more time-consuming than anything, plus there have been enough pictures that I think I can get the idea. The only thing I think I'm missing at this point is torque specs for the upper intake plenum bolts and throttle body bolts. Anybody know the values?

User avatar
vannaksao
Posts: 56
Joined: Mon Mar 29, 2010 2:43 pm
Car: 2003 Nissan Pathfinder SE, 1997 Mitsubishi Eclipse GSX

Post

Don't go nuts with the torqueing. You strip the block or head's thread, you're all done. This is one of those parts where I would go under, instead of over. Be absolutely sure what you torque wrench is set at, and follow the sequences.

Image
Last edited by vannaksao on Tue Dec 14, 2010 7:45 pm, edited 1 time in total.

User avatar
Towncivilian
Posts: 4995
Joined: Sun May 23, 2010 10:21 am
Car: 2001.5 Pathfinder SE 3.5L 2WD A/T
2007 Altima 2.5L CVT
2012 Sentra 2.0L CVT Special
2012 G37 Sedan 7A/T
Location: Florida, USA
Contact:

Post

Excellent, thanks. Will print that page out. Loosen in reverse order means 13-12-11-etc, correct? And install in ascending order? My year's FSM page EM-12 looks a bit different:

Image

User avatar
vannaksao
Posts: 56
Joined: Mon Mar 29, 2010 2:43 pm
Car: 2003 Nissan Pathfinder SE, 1997 Mitsubishi Eclipse GSX

Post

Yea, follow your year FSM if you want. It really doesnt matter, as long as you follow that cross-directional pattern. Yes, you are correct about the descending/loosening, and ascending/tightening order.

User avatar
Chuck Tribolet
Posts: 1490
Joined: Mon Nov 24, 2008 3:15 pm
Car: '01 Nissan Pathfinder, '87 Corvette, '01 Camry daily driver, '98 Boston Whaler Montauk
Location: Morgan Hill, CA and Marina, CA
Contact:

Post

timmack wrote:im pretty sure it applies to all pathfinders/qx4's from 00-04 with the 3.5.
I don't think the 3.5 was available in '00.

The '01 PF with manual transmission does not have a power valve. The automatics do.
Dunno about QX4. Did it ever come with a manual transmission.
There may be some '02 PFs with M/T, and they may or may not have a power valve.


Chuck

User avatar
Towncivilian
Posts: 4995
Joined: Sun May 23, 2010 10:21 am
Car: 2001.5 Pathfinder SE 3.5L 2WD A/T
2007 Altima 2.5L CVT
2012 Sentra 2.0L CVT Special
2012 G37 Sedan 7A/T
Location: Florida, USA
Contact:

Post

I stripped the head of nut #13 and cannot remove it without permanently damaging the nut further, and now require a replacement. Looking at Courtesy Parts' exploded view of Pathfinder (R50) 140 Manifold - INTAKE PARTS: 2001-2004 3.5L , do I require 081B6-8701A? Unfortunately I can't buy it online, so I guess I'll have to go to my local dealer so they can overcharge me.

I also broke the top of a screw that the rearmost engine cover bolt screws on to and was wondering how much a replacement harness bracket would be, but apparently it has no part number. It's shown on the ENGINE COVER PARTS diagram at the bottom but it's not clickable. Is there a part number for it?

Also, to access the PCV valve, does the lower intake manifold have to come off? And is the PCV valve the light blue thing in this picture:
Image

EDIT: Nevermind about the PCV valve, read this thread: post5744448.html

Is there any need to change the PCV valve, or is it not really a maintenance item?

User avatar
Towncivilian
Posts: 4995
Joined: Sun May 23, 2010 10:21 am
Car: 2001.5 Pathfinder SE 3.5L 2WD A/T
2007 Altima 2.5L CVT
2012 Sentra 2.0L CVT Special
2012 G37 Sedan 7A/T
Location: Florida, USA
Contact:

Post

Nissan no longer sells the bolt I require, so time to scour the junkyards for it. Might as well get all 13 and that bracket, I guess.

Tunerguy1989
Posts: 30
Joined: Mon Oct 12, 2009 10:34 am
Car: Nissan Pathfinder LE 2001

Post

What is the point of this procedure what does it do for the car? My bad if this was answered before.

User avatar
Towncivilian
Posts: 4995
Joined: Sun May 23, 2010 10:21 am
Car: 2001.5 Pathfinder SE 3.5L 2WD A/T
2007 Altima 2.5L CVT
2012 Sentra 2.0L CVT Special
2012 G37 Sedan 7A/T
Location: Florida, USA
Contact:

Post

Tunerguy1989 wrote:What is the point of this procedure what does it do for the car? My bad if this was answered before.
The screws holding the butterfly valves (aka power valves) can come loose after a period of time and get sucked in by the engine, potentially causing severe engine damage or failure. Putting threadlocker on them prevents them from vibrating loose and backing out.

JReask
Posts: 31
Joined: Thu Feb 17, 2011 8:05 pm
Car: 2002 Infiniti QX4

Post

I took the plunge last weekend and tore it down enough to check the 12 screws. Many thanks to the OP who supplied the instructions and illustrations. I have to tell you that only two of my screws were "loose". These two screws were loose enough to be turned by finger and the remainder were tight and removed with a screwdriver. I locktited them all and then re installed them. I am no mechanic and it took me about two hours, including a trip to O'Reilly's to purchase a hex socket for TB removal. The peace of mind was definitely worth it. Now if I can just get the sewing machine like ticking figured out. Don't know if it is injectors or not. Are these engines fairly noisy?

tbsbiker2
Posts: 67
Joined: Mon Mar 09, 2009 5:36 am
Car: 2001 SE Pathfinder

Post

I also finally took care of this on my 01 SE with 71,000 miles. I did buy the Felpro gasket set from Autozone $28 for ALL the upper gaskets (the top plenum which is metal) and I'm glad I did as there is a crush aspect to it when it gets torqued down and plus they are coated with something and some if it was coming off or stuck to the intake. Anyway ALL my screws were super tight which I wasn't expecting so there was no problem lurking on my vehicle. I do feel better now about having done it. THANKS AGAIN to all this great forum info. I would have never tackled it otherwise. And for the most part it was just lots of connections and taking logical time to carefully reinstall and torque the intake and throttle body.

MOSTLY I'm glad I changed my plugs even at 71K there was noticable difference between the wear on the OLD plugs vs the new Platinum plug of the same brand and part number. THe truck ran very smooth prior and some of the plugs looked a bit "off" perhaps from the prior Coil Issue that was present shortly after I bought the truck. Anyway runs super super smooth now. THANKS EVERYONE!

User avatar
Towncivilian
Posts: 4995
Joined: Sun May 23, 2010 10:21 am
Car: 2001.5 Pathfinder SE 3.5L 2WD A/T
2007 Altima 2.5L CVT
2012 Sentra 2.0L CVT Special
2012 G37 Sedan 7A/T
Location: Florida, USA
Contact:

Post

Ordered all 13 upper intake manifold bolts/nuts from Rob Lacy of McKinney Nissan in Texas, who was able to source them from Infiniti, strangely enough. Hopefully I'll have them by the end of the week, or next week at the latest and I can finally get some threadlocker on the damn power valve screws. I also bought replacement brackets which have the engine cover studs since one broke and the other is bent and will likely break soon. This time I'll be sure to avoid tightening the engine cover (among other things) to 80,000 hojillion ft-lbs of torque so I don't break another stud, or worse, some other bolt.

User avatar
Towncivilian
Posts: 4995
Joined: Sun May 23, 2010 10:21 am
Car: 2001.5 Pathfinder SE 3.5L 2WD A/T
2007 Altima 2.5L CVT
2012 Sentra 2.0L CVT Special
2012 G37 Sedan 7A/T
Location: Florida, USA
Contact:

Post

Finally put red threadlocker on the power valve screws today at 126,460 miles. All 12 screws were tight and accounted for, and short of having a bit of difficulty getting the throttle body off due to lack of proper tools it went rather smoothly. There was a lot of carbon build up in the upper intake manifold collector. Having that and the throttle body off allowed me to clean them thoroughly. I replaced the two UIM gaskets and the throttle body gasket. Only thing I need to do now is allow enough time for the threadlocker to cure and roll by Nissan to see if they'd torque my throttle body to spec for free or really cheap...

User avatar
donald
Posts: 282
Joined: Mon Jan 10, 2011 9:44 pm
Car: 2001 Infiniti QX4 (RIP, 2011)
2010 Pathfinder LE
Location: Elk Grove, CA

Post

TC, you don't have a torque wrench? you should drop by the Harbor Freight store and pick yourself up one. Sometimes you can nab one for $10+tax.

BTW, how long did it take you with the lack of "proper" tools, as you mentioned?

and just in case - I hope you didn't use any liquid gasget or RTV in place of your "paper" gaskets. I did that on another care of mine, and I can't get my UIM off now :(

anyway, good update!

User avatar
Towncivilian
Posts: 4995
Joined: Sun May 23, 2010 10:21 am
Car: 2001.5 Pathfinder SE 3.5L 2WD A/T
2007 Altima 2.5L CVT
2012 Sentra 2.0L CVT Special
2012 G37 Sedan 7A/T
Location: Florida, USA
Contact:

Post

I do indeed have torque wrenches - 1/2" drive and 1/4" drive (for smaller things). I used the 1/4" drive for everything (including the UIM bolts which were torqued to 168 in lb - all other bolts for brackets torqued between 85-90 in lb). I didn't have the proper hex key that fit the throttle body, so my friend/helper just screwed it back in with some sort of ghetto arrangement of an Allen key and some pliers (similar to how we removed the TB in the first place). It took us maybe 3.5 hours total time actually spent over the span of 9 hours - we had a lot of distractions (a couch arrived at my house, we had to run out to get food, and we needed to go to said friend's house to retrieve said Allen key) and I spent some time cleaning the UIM and throttle body well. I used no sort of liquid gasket. The gaskets are metal-backed and quite sturdy, I could've probably cleaned and reused the old ones, but decided not to for good measure. When opening the throttle body gasket from the plastic bag it came in I tore the bag with too much force and bent the gasket, but I simply bent it back into shape carefully and used it. I'm sure it flattened out completely during reassembly.

I went by the dealership earlier to see if they'd torque the TB, but their computers were down (I had a printout of the FSM page with the torque spec and tightening order, ha) but they were also swamped with customers. Service adviser said I could come back later, but I had to go to class 50 miles away. Nothing fell apart and everything was fine (had a couple short WOT runs), so I'm not awfully worried. I'm thinking the dealer will charge me though since the intake tube must be removed, so perhaps I'll just find another friend with the proper hex key and I'll retorque it myself. FSM says to replace throttle body gasket every time it's "removed" but I wouldn't be removing it completely, just loosening bolts then tightening to spec in order per FSM, so I'll use my day-old gasket. :)

User avatar
Towncivilian
Posts: 4995
Joined: Sun May 23, 2010 10:21 am
Car: 2001.5 Pathfinder SE 3.5L 2WD A/T
2007 Altima 2.5L CVT
2012 Sentra 2.0L CVT Special
2012 G37 Sedan 7A/T
Location: Florida, USA
Contact:

Post

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 guide 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.

User avatar
Towncivilian
Posts: 4995
Joined: Sun May 23, 2010 10:21 am
Car: 2001.5 Pathfinder SE 3.5L 2WD A/T
2007 Altima 2.5L CVT
2012 Sentra 2.0L CVT Special
2012 G37 Sedan 7A/T
Location: Florida, USA
Contact:

Post

I have fixed the images, formatting, and link to the original NPORA thread on the first post.

User avatar
CanuckQx4
Posts: 1379
Joined: Mon May 03, 2010 10:45 am
Car: 2001.5 Qx4 2wd

Post

Ive never changed my PCV valve, why did you change yours this time around??

I dont think I even see mine when I pulled the upper plenum off to tighten the screws

User avatar
Towncivilian
Posts: 4995
Joined: Sun May 23, 2010 10:21 am
Car: 2001.5 Pathfinder SE 3.5L 2WD A/T
2007 Altima 2.5L CVT
2012 Sentra 2.0L CVT Special
2012 G37 Sedan 7A/T
Location: Florida, USA
Contact:

Post

The PCV valve is below the lower intake plenum. I changed it because I felt that at 128k miles, it probably wouldn't be a bad idea to change it out. Preventative maintenance, basically.

Apparently I didn't link the topic I made about the replacement procedure earlier: click.

Theory_EK
Posts: 9
Joined: Thu Jun 19, 2008 8:52 am

Post

So all I have to do is remove the upper plenum and tighten those 12 little screws on the butterfly valve with locktight? Do any fluid lines need to be unplugged with doing this? I plan on doing this next weekend. Also for the PCV valve I did the one on my g35 and was wondering if its in the same location. The one on my g35 was on the front pass side valve cover.

User avatar
Towncivilian
Posts: 4995
Joined: Sun May 23, 2010 10:21 am
Car: 2001.5 Pathfinder SE 3.5L 2WD A/T
2007 Altima 2.5L CVT
2012 Sentra 2.0L CVT Special
2012 G37 Sedan 7A/T
Location: Florida, USA
Contact:

Post

Theory_EK wrote:So all I have to do is remove the upper plenum and tighten those 12 little screws on the butterfly valve with locktight? Do any fluid lines need to be unplugged with doing this? I plan on doing this next weekend. Also for the PCV valve I did the one on my g35 and was wondering if its in the same location. The one on my g35 was on the front pass side valve cover.
All you need to do is remove the upper intake plenum and reseat the tiny screws with threadlocker (preferably red), yes. The PCV valve is in the same place as the G35 (passenger side valve cover). See my thread I linked for parts required if you wish to tackle the PCV valve, otherwise the first post has the gasket part numbers required for taking off the upper intake plenum to access the power valve screws (you'll only need the first three if you don't plan on removing the lower intake manifold).

Good luck!

Theory_EK
Posts: 9
Joined: Thu Jun 19, 2008 8:52 am

Post

Thanks man! I just replaced the s*** oil cooler seals today. It was pretty simple and I got to brake clean the s*** out of the bottom of the chassis so it looks new now lol.

Theory_EK
Posts: 9
Joined: Thu Jun 19, 2008 8:52 am

Post

This job was a breeze and honestly if you can change your oil you can do this. I just removed the upper intake manifold disconnect all the hoses and clips connected removed the whole assembly. No need to disconnect the throttle body from the manifold. I had all my screws and they were all tight. I secured them with 27200 thread locker its a high temp high strength red thread locker. Thanks for the pics and torque specs guys!

User avatar
Towncivilian
Posts: 4995
Joined: Sun May 23, 2010 10:21 am
Car: 2001.5 Pathfinder SE 3.5L 2WD A/T
2007 Altima 2.5L CVT
2012 Sentra 2.0L CVT Special
2012 G37 Sedan 7A/T
Location: Florida, USA
Contact:

Post

I'm glad all screws were present and that the process went smoothly for you.

How did you manage to remove the upper intake manifold without removing the throttle body? Did you just remove the top two bolts?

Theory_EK
Posts: 9
Joined: Thu Jun 19, 2008 8:52 am

Post

Sorry I did remove it I just didn't remove it from the plenum. I never undid the 4 bolts securing it to the upper. Does anyone know what that tube that comes up from the back of the engine and it plugged off? It like sit right behind the upper plenum. I always wondered what it was.


Return to “Nissan Pathfinder Forum / Infiniti QX4 Forum”