3.5L Valve Cover Gasket Project

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The Grand Pooh-Bah
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Has anyone made a list of all the recommended parts you need to order prior to replacing the valve cover gaskets for the 3.5L? I'd like to get the parts from partsnext.com so I'd really like to get everything in one shipment.

I'm leaning towards being proactive in replacing anything and everything that might be a concern in the future. Considering the pure age of the engine I am going to consider all rubber parts have run their course of reliability.

Any speciality tools needed?

Thanks In Advance.

New owner of 2001.5 QX4


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mdmellott
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14032-4W00A - Lower plenum gasket
14033-4W000 - Upper plenum gasket
14033-4W010 - Upper plenum gasket
16175-4W000 - Throttle body gasket
13270-8J112 (prod date 07/01) - Valve cover gasket
13270-8J102 (prod date 07/01) - Valve cover gasket
13276-AH100 - Oil filler o-ring
11823-4W00A - Blowby hose (dried out and hardened old hose will likely crack when removed)
11826-5W500 (prod date 07/01) - Blowby hose (dried out and hardened old hose will likely crack when removed)
11810-8J102 (prod date 08/01 - 07/02) or 11810-31U00 (prod date 0/00 - 08/01) - PCV valve
11812-41B00 - PCV valve insulator (only needed for non-threaded PCV valves)

Double check with a dealership for the production date/part numbers required for your 2001.5 QX4. I indicated what I believe would be the correct parts for yours but I have found that many online resources get these details wrong and even the dealerships sometimes struggle to get it right, given all the updates Infiniti and Nissan sometimes fail to consistently keep track of. The PCV valve is a good example of this. Dealerships and online resources indicate an insulator is needed but it's not needed if the PCV valve has a threaded connection into the valve cover. Partsnext.com has great prices and delivery but you will not likely get a refund for returns to the UAE if you order the wrong parts. (Been there, done that. It sucks but I still saved money overall.)

No special tools are needed, other than a good RTV silicone sealant for a very limited area at the corners of the valve cover gaskets. Refer to page EM-38 https://www.nicoclub.com/service-manual ... 5%2Fem.pdf I also noticed that thread lock sealant (the blue type) is applied to two of the four lower plenum bolts, indicated as bolts 1 and 2 in the tightening sequence diagram on page EM-13. You may notice this as well when you remove those two bolts. No where in the service manual do I see that it is required but it was applied at the factory on my Pathfinder and it makes sense that those two bolts should have this extra assurance of securing them, but only those two bolts. (Trust me on this one. I didn't want to write up a lengthy explanation as to why that thread locker is needed.)

AlanAZ
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There is an upper thermostat, mounted in the middle of the V, which some people here recommend replacing. I also recommend switching the front spark plug coils with the back, to spread the heat load.

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The Grand Pooh-Bah
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What about the spark plug tube seals? I read somewhere that these can be an issue.

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mdmellott
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The Grand Pooh-Bah wrote:
Sun Jun 06, 2021 9:59 am
What about the spark plug tube seals? I read somewhere that these can be an issue.
Good question but this has a sad backstory. Those seals are one item I was burned on, after I purchased them from PartsNext and then realized, after removing my valve covers, the seals cannot be replaced. Nissan got this wrong when I inquired about them, before my purchase, and online resources like Nissan Parts Deal and Infiniti Parts Deal have these indicated as a separate and presumably replaceable part when in fact the tube seals (not the ones indicated) are irreplaceably integrated into the plastic valve covers. My inquiry to Nissan was to get an answer to why only a total quantity 3 is shown as the number needed when obviously there are 6 of them and, to make things more confusing, there are two OEM supply makers indicated (NOK and NDK) and 2 different part numbers, each showing a quantity of 3 required. I was ill-informed that was a typo not only with third party online resources but also currently reflected on Nissan's parts listing as well. The seals indicated are actually for older style aluminum valve covers but, by the time I found this to be the case, I had already purchased the parts. If you have the older style aluminum valve covers, which I doubt because the part numbers of the covers and seals I find for your QX4 are the same for my Pathfinder, then those seals would be advisable for replacement. Otherwise, replacing the entire plastic valve cover with integrated seals is your best option. Not the only option however. With a hole saw and copious amounts of RTV silicone sealant, I have seen videos of others crafting a retrofit replacement set of seals into their plastic covers. Mine were not leaking and are still intact so I passed on the risk of wrecking my covers. Others have simply replaced the old plastic covers with RTV silicone sealant to stop up any leaks in cracked tube seals.

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VStar650CL
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If you grease the outsides of the tubes with vaseline and then run a bead of sealer around the top of the old seal, the vaseline will allow the sealer to do its job without sticking to the tube and making future removal difficult.

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The Grand Pooh-Bah
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My valve covers are aluminium, that's a good thing, right? So do I need to order seals for them?

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The Grand Pooh-Bah
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Also, should I replace the seals under the bolts that hold the valve cover on?
(20) 13268-AD20A

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VStar650CL
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The Grand Pooh-Bah wrote:
Sun Jun 06, 2021 4:55 pm
Also, should I replace the seals under the bolts that hold the valve cover on?
Anything rubber is a no-brainer. The more of it you replace now, the less likely you are to need to repeat the job anytime soon.

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mdmellott
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The Grand Pooh-Bah wrote:
Sun Jun 06, 2021 3:18 pm
My valve covers are aluminium, that's a good thing, right? So do I need to order seals for them?
That's a good thing, I guess, but it also means you would have sealing washer/standoffs 13268-AD20A (qty 20). The plastic covers have shoulder bolts and plain metal flat washers. The rubber seals on those metal washer/standoffs are also likely to be hard and no longer flexible enough for them to seal well in the aluminum cover mounting holes. The valve cover gaskets I indicated may not be the right ones for you either. I know they fit the plastic covers because those are what I purchased but I don't know if they are right for the aluminum covers. It may be part numbers 13270-4W000 and 13270-2Y510 you need instead but it would be best if you confirm all of this with a dealership, using your VIN to be sure. The blow-by hose 11823-4W00A I indicated may actually be 11826-4W010 for the aluminum cover and the PCV valve it attaches to may be 11810-31U00. I purchased the other one I indicated, which was threaded. I assume 11810-31U00 would be a non-threaded type and therefore the PCV insulator would also be needed. As for the tube seals and the two different part numbers made by NOK and NDK (13276-31U1A and 13276-31U21), as with all these parts, I would recommend confirming with a dealership the part numbers you need before you order anything.

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mdmellott
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mdmellott wrote:
Sun Jun 06, 2021 5:53 pm
... you would have sealing washer/standoffs 13268-AD20A (qty 20)...
... which you already know about and I am very slow in typing my replies.

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VStar650CL
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mdmellott wrote:
Sun Jun 06, 2021 6:13 pm
... which you already know about and I am very slow in typing my replies.
Pish tosh, we all love you anyway. :yesnod

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mdmellott
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The Grand Pooh-Bah wrote:
Sun Jun 06, 2021 4:55 pm
Also, should I replace the seals under the bolts that hold the valve cover on?
(20) 13268-AD20A
I sent you a PM about tube seals, sealing washers and a PCV insulator I have no use for. The cost would be one smiley face emoji in reply to this and a response to my PM.

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The Grand Pooh-Bah
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:shifter: :yesnod :woot: :bowrofl: :BnB:

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The Grand Pooh-Bah
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Got all of the parts ordered. Unfortunately partsnext.com didn't have aprox. 1/2 of the needed items. Got the missing parts from the closest dealer, 300 miles away.
A special Thank You to mdmellott for the parts he didn't use on his project!!

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The Grand Pooh-Bah
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This project is now underway. Did the drivers side with no issues.

Do you have to remove the fuel rail to get the passengers side cover off and access the thermostat at the back?

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mdmellott
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I didn't but is was a bit of a puzzle to lift and maneuver the cover off and out while avoiding what appears to be obstructions and not excessively forcing it to squeeze past these parts that do not have to be removed. Just remember how you manipulate it out so you can install it in reverse motions. My new OEM gasket kept falling off in the process of installing it so I ultimately used a sparingly small amount of RTV sealant to hold it in the groove of the cover.

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mdmellott
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The Grand Pooh-Bah wrote:
Sat Jul 03, 2021 11:44 am
... access the thermostat at the back?
I don't have a thermostat at the back. There is an engine coolant temperature sensor at the rear, which is inconveniently hidden by the intake plenums, but no coolant thermostat on mine in the rear.

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The Grand Pooh-Bah
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Mine has 2 temp sensors and a thermostat at the rear of the engine. I broke one of them trying to unplug the wires.

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mdmellott
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Ok. Made me look. I do have a thermostat type valve back there on mine, hiding behind the intake manifold. Nissan/Infiniti call it a water control valve. To access that on mine I would have to remove the intake manifold. I never had to do that and it wasn't in my way when I removed my valve covers. It's crazy that so many seemingly simple and fairly low cost maintenance items turn into complicated and costly operations because those items are buried under or behind major engine components that have to be removed first.

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The Grand Pooh-Bah
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I thought I had everything I needed when I started this quick little project. I just keep getting deeper and deeper into this.
I just ordered
14056-4W000 1 $ 14.23 Engine Coolant Hose
11062-4P100 1 $ 2.43 Gasket Water Outlet.
14055-4P110 1 $ 9.38 Engine Coolant Hose
21230-6N20A 1 $ 10.32 Engine Coolant Thermostat
14035-38U01 2 $ 23.50 Engine Intake Manifold Gasket
22630-44B20 1 $ 23.90 Engine Coolant Temperature Sensor
25080-89907 1 $ 18.23 Engine Coolant Temperature Sensor
Uremco 2-6 1 $ 14.61 Fuel Injector O-Ring Kit (All 6 Injectors)

If I didn't dig a bit deeper and replace the hoses and thermostat under the intake manifold I just know it would haunt me. Turns out to have been a good choice. The intake manifold was extremely dirty inside. More purple cleaner and scrubbing did the trick.

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The Grand Pooh-Bah
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I also replaced the
Fuel Filter
Fuel Injectors
Spark Plugs
Air Filter

Cleaned the
MAF Sensor
Throttle Body
Upper & Lower Plenum's
Intake Manifold

Performed the Power Valve Screw Service

Fired it up last night and it is running rough.
Ran it this morning and this is what is happening?

https://i.imgur.com/FlUx1WY.mp4

Fuel Pressure Regulator?

HELP!!!

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mdmellott
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The Grand Pooh-Bah wrote:
Sun Jul 18, 2021 9:56 am
Fired it up last night and it is running rough.
Ran it this morning and this is what is happening?
Kind of sounds like it's misfiring or there's a serious vacuum leak but (and hopefully) it is just temporarily stuck in old memory operating conditions. Given the temp sensors and injectors you replaced, the engine has to relearn what its optimum operating settings are. The new injectors can be troubling at first if there is any difference at all in flow rate compared to the old injectors because your ECM memory only knows to vary pulse width based on operating conditions. Even if nothing else changed except the slight difference in flow rate, your ECM has to relearn what the new pulse width modulations need to be in order to rebalance the air/fuel mix ratio. Throw in the new sensors, and the ECM has to relearn what those potential variations are as well.

This relearn process could take a couple of cycles of self diagnostic monitoring but it's very good at walking and chewing gum at the same time. You should take it for a casual ride, 10 minutes or so, to see if it settles in to a smooth operation. If there is anything serious going on, like a misfire or intake vacuum leak, your check engine light should let you know. If you have a scan tool with live data monitoring, it would be a good idea to see what is happening with fuel trim, O2 sensors, ECT sensor, MAF sensor, and air temp sensor if this rough running condition does not settle down.

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mdmellott
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One more note on the obvious from the video: If the water dripping profusely out of your tail pipe and resonator does not dry up after driving around 10 minutes or so, there is water in your tank that needs to be expelled. That will dampen your combustion event badly and cause rough running and misfires.

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The Grand Pooh-Bah
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One of the new injectors was bad. It was spewing gas into the #8 cylinder with no power applied. That was gas flowing out of the tailpipe.

Got it back together and it is purring. This project is in my rear view mirror. :dblthumb:

Thanks for all the help and advice!!! :bowrofl:

Next project. Boots on the Steering Rack.

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mdmellott
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The Grand Pooh-Bah wrote:
Sun Jul 18, 2021 5:29 pm
That was gas flowing out of the tailpipe.

Got it back together and it is purring.
Yikes! That could have wrapped up this project with a bang. It's great to hear that all is now well and nobody had to hear any fireworks. I've seen fuel saturated cats that had ignited like a cannon and blew their guts out, no longer to purr as usual. Great catch on that potential disaster.

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The Grand Pooh-Bah
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Just a follow up after running around Idaho today with the A/C running. I drove just over 200 miles today. Our terrain has very few flat stretches and the transmission has to drop down a gear to climb frequently. I was pleased to get 18.6 MPG. She most definitely is purring. No more smell of burning oil dripping onto the exhaust manifold. Only drips under the vehicle are from the A/C condensate. :woot: :woot:

Pathyj1
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@mdmellott and @The Grand Pooh-Bah, I just wanted to say thank you for sharing what you've learned for this particular job. I've replaced other valve covers before (primarily Toyotas) and the way this engine is configured and the lack of Nissan's documentation seems to make this more confusing. This particular post is the only place I'm seeing anything conclusive and helpful.

I have a 2001 Pathfinder SE (mfg date of 03/2001) with aluminum covers and I'm taking note of all the info you shared above. Will probably place a big order on Partsouq, which is also in the UAE and seems to have more availability and schematics than Partsnext. I've ordered from them for my Toyotas with no problem, at half the price compared to the US retailers.

I HATE starting a job and not having the right parts ready to go, so I'm a bit hesitant to get this going, but I'll do my best to inventory the parts and roll the dice!

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mdmellott
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Pathyj1 wrote:
Tue May 17, 2022 1:05 pm
@mdmellott and @The Grand Pooh-Bah, I just wanted to say thank you for sharing what you've learned for this particular job. ...
You are very welcome and thank you for taking the time to register as a member of NCOclub and making this your first post. I appreciate knowing for certain this has helped others.
:welcome: :luck:

Pathyj1
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Thank you for the welcome! I will most definitely have many more posts.

This is a new-to-me 2001 PF SE, with 160k mild miles, that I've slowly been baselining and want to last for many more miles, even for off-roading, without marking its territory everywhere. I've reviewed the above recommendations of parts to replace while I'm doing the valve cover gaskets and landed on these specific part numbers for my 03/2001 PF.

Am I missing any parts, especially rubber and gaskets, that absolutely should be done while deep into the valve cover gaskets? I'd rather err on getting too many parts than not enough, since I figure they'll be needed eventually.

16175-4W000 Throttle body gasket
14033-4W000 Upper plenum gasket
14033-4W010 Upper plenum gasket
14032-4W00A Lower plenum gasket
14035-38U01 Intake lower gasket (2x)
13270-4W000 Valve cover gasket
13270-2Y510 Valve cover gasket
13268-AD20A Valve cover washers (20x)
13276-31U21 Spark plug tube seals (6x)
11810-31U00 PCV valve
11812-41B00 PCV valve insulator
11826-4W010 Blow by hose to PCV
11826-4W005 Blow by hose to pipe assembly
11826-4W002 Blow by hose 2-curves
11823-4W00A Blow by hose 2-curves largest
13276-AH100 Oil filler o-ring
14055-4P110 Short water hose
14056-4W005 Long C water hose
14056-4W000 Long L water hose
11062-4P100 Water outlet gasket
11062-AL51A Water outlet gasket (2x)
21230-6N20A Thermostat
21049-6N220 Thermostat o-ring
22630-44B20 Coolant temp sensor
25080-89907 Coolant temp sensor
Uremco 2-6 1 Fuel injector seal kit (from Amazon)
Spark plugs... any recommendations?
Loctite power valve screws
RTV


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