1. Ride it till it dies.
2. oil injector issue most likely additive won't help.
3. keep regular maintenance and if nothing else than the noise you are good.

 

This 👆

 

I'm one of the "engine-knock survivors" who had his short-block done under warranty. Nissan has never come clean on an explanation for the issue.

But, after reading the available Technical Service Bulletins (TSB's) on the topic, many of us on here concluded the instructions in the TSB's gave away the cause. Nissan specifies to the tech to realign the oil injector that serves the lower part of the #7 cylinder.

Thus it seems to be a tacit admission that a manufacturing error in said alignment is behind the scoring. Some people get it; some don't.

Some other observations:

• The "knock" is actually piston slap.
• By the time you hear the sound, it is too late to pre-empt the failure.
• No one has come forward and said "my engine ate itself because of the issue."

Finally, I've not read any report of Nissan stepping up after the warranty period has passed. I wish I could deliver better news, but that seems to be the case.

So as @feraille said, just drive it. And I would add, turn up the radio if it helps.

PS via edit: The Engine Knock (Piston Slap) Thread

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Also edited for the usual basketcase speelin' and missing word issues due to his stroke affected eyesight...

 

But, after reading the available Technical Service Bulletins (TSB's) on the topic, many of us on here concluded the instructions in the TSB's gave away the cause. Nissan specifies to the tech to realign the oil injector that serves the lower part of the #7 cylinder.

I keep reading this over and over and I really can't see how anyone is coming to this conclusion.

The TSB does mention oil injector seating and orientation, but they are for the timing chain on the front of the motor. You can clearly see in the below graphic from the TSB the timing chain guides and the crankshaft snout on the front of the motor. These would have nothing to do with cylinder wall lubrication. And these engines do not have under cylinder oil sprayers. Cylinder walls are lubricated by oil squeeze out of the rod bearings.

Why are they included in the TSB? Good question. I would imagine they don't come installed on the short blocks from the factory and Nissan wants them hand fitted? Your guess is as good as mine.

Do I know exactly what caused this? No. And I bet Nissan is never going to come clean about it either. But the oil sprayer cause doesn't become any more true just because everyone repeats it.

Ok, rant over. I know it doesn't matter what the cause is to the affected owners (including me), I just think we should be accurate here.

Have a great weekend.

 

Thank you for such detailed explanation! Much appreciated! Quite reassuring that it could be driven, definitely don't want to sacrifice safety! @basketcase

 

@basketcase Thank you for not taking offense to me tagging your statement. I was only referencing the realigning of the oil squirter cause and you happened to reference it last.

I have also read much, though probably not all of the mega-thread. I don't remember seeing another TSB that had any other graphic or description of the oil jet though I could be wrong. I will need to skim through it again.

The TSB I snipped is the latest, NTB19-057a, that was released in 2020. The latest and most up to date one, NTB19-057a, pushed the date of the affected vehicles out another year or so. The original, NTB19-057, was released in 2019. These are the only two versions I'm aware of and I have attached both of them, downloaded from the nhtsa.gov website. As far as the Oil Jet Installation section between the two, they look identical to me.

I'm no engine builder but I do have basic knowledge of engine lubrication. Oil is pressurized through the crank and pressurized oil flows between the crank and rod berings. Through the rotation of the engine, some of this oil leaks out the gaps on the sides of the berings and gets slung up under the piston and onto the piston walls. The youtube video here explains better than I can. Right at the 3:00 minute mark.

The only oil squirters that I'm aware of that would lubricate under the pistons and cylinder walls are piston cooling jets, like those used in some of the Ford Coyote 5.0 engines. The Nissan 5.6 does not have them. Their primary purpose isn't to spray the cyllinder walls. They spray the bottom of the piston to help cool it in high compression scenarios. Here are a couple pictures of them in a Coyote I scrapped off the internet.

The only conceivable way I can think that not seating a timing chain oil sprayer on the the front of the engine could affect cylinder oil spray on the rear cylinders would be that some how the non-seating of them properly blocks an oil passage, dropping oil pressure to the whole crank. The oil goes front to back, so cylinder 7 and 8 would be most affected by a low oil pressure situation. And get inadequetly lubricated?

Seem like if this was the case, we would have engines with cooked main and rod berings as well. But there has been many that have just kept on driving them knocking and they at least don't seem to fail very prematurely. If I was to make a guess, I bet the cause of the issue is too loose of fitment of piston to cylinder, defective pistons of some sort, or a metalurgical issue. Heck, maybe a mixture of all three.

I hope I was able to better explain my thoughts on this. Thanks for reading all this if you made it this far

 

I think a lot more engines are coming with oil squirters for cooling, like you found on the ford engine.

As gar as what the nissan oil jets are doing, i have no idea. You maybe roght thay they were turned just enough to stop oil from going past them enough to supply to the number7 but its weird.

I cannot find the three TSBs i had saved from the engine scuffing issue inhad found back when i got my truck in 20

 

Wasn’t there a mention at one time of the #7 cylinder issue coming from a slightly out of round #7 during the machining process? I asked for mine to be checked when I was still under warranty and the dealer claimed there was no scoring and provided 1 photo of the cylinder. I was never sure if I was actually hearing a knock or just paranoid from the thread. Now I’m out of warrant, so I hope it was just paranoia.