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.The Grand Pooh-Bah wrote: ↑Sun Jun 06, 2021 9:59 amWhat about the spark plug tube seals? I read somewhere that these can be an issue.
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.The Grand Pooh-Bah wrote: ↑Sun Jun 06, 2021 4:55 pmAlso, should I replace the seals under the bolts that hold the valve cover on?
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.The Grand Pooh-Bah wrote: ↑Sun Jun 06, 2021 3:18 pmMy valve covers are aluminium, that's a good thing, right? So do I need to order seals for them?
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.The Grand Pooh-Bah wrote: ↑Sun Jun 06, 2021 4:55 pmAlso, should I replace the seals under the bolts that hold the valve cover on?
(20) 13268-AD20A
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.
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.The Grand Pooh-Bah wrote: ↑Sun Jul 18, 2021 9:56 amFired it up last night and it is running rough.
Ran it this morning and this is what is happening?
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.The Grand Pooh-Bah wrote: ↑Sun Jul 18, 2021 5:29 pmThat was gas flowing out of the tailpipe.
Got it back together and it is purring.
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.