DIY: Threadlocker On Power Valve Screws

[Towncivilian]

Oh, you didn't remove the lower intake manifold. I didn't either when I put threadlocker on the screws.

That tube is the air relief valve. You're talking about the item in the center of this picture, correct?



It's used during drain & fills of the radiator to help burp air.

[nico911411]

Guys,
My valve covers leak oil! Will I need to also remove the lower manifold for easy access to valve covers & seals? And is there a way I can relocate the PCV Valve for easy replacing if ever needed?

[Towncivilian]

Yes, you will need to remove the lower intake manifold and the fuel rail to access the valve covers. I don't think there is a way to relocate the PCV valve unfortunately.

[nico911411]

The fuel rail too REALLY? I guess I'll need to remove whatever is in the way of removal of valve covers!

[hirk]

Btw it has been said pathys made in japan didnt have this issue, well my 2004 was made in japan and it was missing 2 screws and a butterfly plate when i opened it up and had no thread sealer on any of the screws.

[Towncivilian]

As far as I know, all years of Pathfinders and QX4s with the VQ35DE engine are at risk of this problem. I've read of such disqualifiers (Made in Japan, 2004 not affected, etc) but this is apparently not the case. I find it odd that there is not even a technical service bulletin about this issue. It may be a rare issue for screws to back out, but I've seen TSBs on even more obscure subjects than this one.

[Buzzman]

After reading about this for years, and two years after I bought the necessary gaskets, I finally got around to doing the power valve screws today.
It wasn't as hard as I thought. I only removed the upper plenum. I left pretty much everything attached to it, including the throttle body assembly.
There is no need to remove the lower plenum, as far as I'm concerned.
I pulled off a couple of vacuum lines to give myself some wiggle room, and that was it.

As for what I found: all I can say is, whew!
All valves were present and accounted for, and all the screws were there, nice and tight. Absolutely as it should be.
I put a dab of loctite on them anyway, but if I hadn't, I would still feel confident that they would hold.
All in all, I probably only spent about an hour and a half on the whole job.

[nico911411]

I need to remove the lower manifold.
Do I also need to remove those 2 bolts - 12mm (circled) holding the supporting bracket? would a crowfoot wrench help in removing these?
or Do I need to remove just 1 bolt down below (black circled)? would be easier?

[Towncivilian]

You can try to remove the black bolt but I don't know how easy it'll be to access. For the red bolts, mine were already loose enough to rotate relatively easily, though it was still the most irritating part of the job. There is next to no clearance to access those bolts in the engine bay.

[nico911411]

i was replacing the seals for both valve covers, but the manual suggests to only tighten those 10 bolts/valve cover to 6.9 - 8.8 N.m TWICE

is this right? seems way too loose?

is this possible to replace those 3 rubber seals for sparkplug holes? these valve covers are plastic and i don't want to break them.

[kcc225]

I bought the necessary gaskets and pcv valve and did the power valve screws yesterday. It took me 7 hours included 2 hours to home depot by BUS to pickup a 12mm long sleeve socket (I have to, because the car was half way in to removing the lower intake manifold, two bolts required 12mm long sleeve socket, and I can't find my!!!). All 12 screws were still attached to the valve, but 4 screws were loose to the point I can turned it with my finger!!! Take my time and do it slow to make sure I didn't miss any thing, and YES, the most irritating part of the job was to remove the red bolts in the picture. At least, I got every thing done at once!

[Towncivilian]

Glad to hear you were able to do the job. Looks like you made it in time since none of the screws had been ingested. It's scary to think that they were loose though, who knows how long they were loose for?

[robbykennedy]

Guys I am getting ready to do this job. I am also going to take the opportunity to replace my spark plugs, I have 86K on my 03 pathfinder.

What should I expect to replace while doing this job in addition to the spark plugs?.
PCV valve?

And what gaskets do I need to replace ?

Should I also replace the valve cover gasket?. I do not think my valve cover gasket is not leaking but what if it were to leak in a few months from now.

[Towncivilian]

PCV valve is a good idea. You will need to replace the throttle body gasket, 2x upper intake manifold gasket, and lower intake manifold gasket. You do not need to replace the valve cover gasket.

[robbykennedy]

Towncivilian,

Can I get to the spark plugs without removing the lower intake manifold?. I am getting ready to apply threadlocker on my power valve screws this weekend. I now know that if I want to replace the PCV valve I have to remove the lower intake manifold and I am fully aware about the complications regarding the bolts in the back of the engine where there is little to no clearance at all.

[Towncivilian]

Absolutely, there's a great guide on spark plugs here.

[barnaclebob]

If you are looking for a good reason to buy a borescope, this is it... My wife got me one a couple months ago and it worked great to make sure my screws were still there at 144k miles. I'm going to go with the if it ain't broke don't fix it theory on this one. You just need to remove the rubber duct from the throttle body and hold it open to inspect the screws.

[my2001qx4]

If you are looking for a good reason to buy a borescope, this is it... My wife got me one a couple months ago and it worked great to make sure my screws were still there at 144k miles. I'm going to go with the if it ain't broke don't fix it theory on this one. You just need to remove the rubber duct from the throttle body and hold it open to inspect the screws.

I wish I had bought one a few years ago. I borrowed one years ago but the head wasn't small enough to fit into the spark plug hole I could peek straight down but not all around in the bore. Didn't see a screw or any damage so I went to plan B and C. Years later after the noise was still there I took out motor and pulled heads to find the screw in it. It was way down on piston 1/4 " from edge of piston out of view of the borescope I had borrowed. This car has been parked for four years cause I feel a stupid screw.

[my2001qx4]

If you are looking for a good reason to buy a borescope, this is it... My wife got me one a couple months ago and it worked great to make sure my screws were still there at 144k miles. I'm going to go with the if it ain't broke don't fix it theory on this one. You just need to remove the rubber duct from the throttle body and hold it open to inspect the screws.

I wish I had bought one a few years ago. I borrowed one years ago but the head wasn't small enough to fit into the spark plug hole I could peek straight down but not all around in the bore. Didn't see a screw or any damage so I went to plan B and C. Years later after the noise was still there I took out motor and pulled heads to find the screw in it. It was way down on piston 1/4 " from edge of piston out of view of the borescope I had borrowed. This car has been parked for four years cause I feel a stupid screw.

[Nissanislife]

So I have a question . is there anybody in the DC Maryland or virginia area that would like to use there precious time and help me do this ?? I have beer pizza and a couple bucks .

[my2001qx4]

[quote"my 2001q x4"][.quote=" barnacle bob"] If you are looking for a good reason to buy a borescope, this is it ... My wife got me ,one a couple mo nth.s ago and it worked great to make sure my screws were still there at 144k miles. I'm going to go with the if it ain't broke don't fix it theory on this one. You just need to remove the rubber duct from the throttle body and hold it open to inspect the screws.[/quote]

I wish I had bought one a few years ago. I borrowed one years ago but the head wasn't small enough to fit into the spark plug hole I could peek straight down but not all around in the bore. Didn't see a screw or any damage so I went to plan B and C. Years later after the noise was still there I took out motor and pulled heads to find the screw in it. It was way down on piston 1/4 " from edge of piston out of view of the borescope I had borrowed. This car has been parked for four years cause I feel a stupid screw.[/quote]

Well I have torn the motor down and plucked the screw out of my piston, got everything back together, reassembled and put the motor back in.now it won't start all It does is turn over. I get a 0340 code cam phase sensor. Checked it out following the instructions in the manual it specs out, the wiring is ok. buddy says probably a timing issue. how do you check the CVTS system that it is reset or calibrated correctly? And the cams are in synch it does not say in the manual I have? The timing marks all align with the proper dots and marked chain links. Any help would be greatly appreciated. I am getting tired of tearing this motor down, I have had it apart 3 times already.

[my2001qx4]

If you are looking for a good reason to buy a borescope, this is it... My wife got me one a couple months ago and it worked great to make sure my screws were still there at 144k miles. I'm going to go with the if it ain't broke don't fix it theory on this one. You just need to remove the rubber duct from the throttle body and hold it open to inspect the screws.

I wish I had bought one a few years ago. I borrowed one years ago but the head wasn't small enough to fit into the spark plug hole I could peek straight down but not all around in the bore. Didn't see a screw or any damage so I went to plan B and C. Years later after the noise was still there I took out motor and pulled heads to find the screw in it. It was way down on piston 1/4 " from edge of piston out of view of the borescope I had borrowed. This car has been parked for four years cause of a stupid screw.

[my2001qx4]

Well fixed that problem above. I installed the cam sprocket on the wrong side of the motor. All the teeth the cam sensor was supposed to sense were not there. Now it runs but I am getting a code P 1140

[rube23]

Is it necessary to loctite the screws on the power valves and the swirl valves or are the power valve screws the only issue?
If I followed correctly, The lower intake needs to be removed to Loctite on the screws on the swirl control valves ? I'm. It looking to do that much work lol.

[mppp78]

Wish I had noticed this thread 2 weeks ago when I was replacing valve cover gaskets and I'm amazed I've never had heard of this problem. So from what I've read only the upper plenum needs to be removed though for power valves, correct? Kudos for doing the swirl valves as well, but from what I've read I haven't seen these failing (am I wrong?).