CorollaULEV

https://drive.google.com/file/d/0B4z...ew?usp=sharing

Hey folks - thought I'd share the above oil analysis I just got back on my 2010 Maxima. I have the bearing knock and have since it was new. Further proof that it's not as damaging as you might think.

Later,
Travis

Bificus99

Not totally a 100% accurate way to tell bearing damage versus wear. It is a very useful application so don't get me wrong. And it does surprise me there is little change in metals in the oil. However there is photographic proof that there is damage in the bearing thread. A picture is worth a thousand words.
This sucks if you wanted to monitor this issue without taking the engine apart.

CorollaULEV

Do you really think it's possible to have wear OR damage (the two are kind of synonymous to me) and have a perfectly clean oil analysis? Main or connecting rod bearing wear (or damage) is going to show up with elevated levels of copper, lead and tin.

Also if the bearing has worn significantly, bearing space is larger and oil pressure drops, so essentially aluminum and iron would elevate as well due to inadequate lubrication from low oil pressure.

How many documented failures has the forum seen due to this problem? One? Maybe two?

Bificus99

I agree that there should be elevated metal readings with a knocking engine. I'm also saying the test may not be conclusive for rating the damage with this knock. The failures are rare due to the robust design of the engine. Not many engines can knock this long without catastrophic failure.

KGMtech

I agree. The noise issue is an audible annoyance for most sensitive owners, that explains why the issue doesn't show up on Consumer Reports, True Delta, or other data collection sites. Sensitive and keen owners, people who join model specific sites are a VERY small portion of the total ownership pool, this does change for exotic makes and models ~ sorry but Nissan outside of their 1 hot rod would not have too many owners frequenting car forums.

The noise goes away when the transmission goes into drive, for a knocking engine how much time does the engine spend running in park when warm? IMHO not a big portion of the total run time and clearly not a situation that would place extreme loads on the bearings to cause undue wear.

If the problem was so serious, there would be evidence of Cu, Tin, Pb bearing metals in each of the OP's UOA and then the Fe and Al would spike due to loss of system oil pressure from too large clearances in the bad bearing, plus the knock would become louder and not go away as revs increased. Then the engine would fail...boom boom out go the lights

This knock problem is annoying, it is not something I'd be happy to have on my VQ35DE, but if Nissan did nothing for the affected owners, it would not leave you stranded. Pissed, yes, but not pushing.

1996blackmax

iTrader: (2)

I would have thought the opposite. I'm glad your engine is doing well.

CorollaULEV

Ya know, I was looking through the bearing thread and apparently, the guy whose main bearing was found laying in the oil pan had purchased the car used and there was question as to how well the car had been maintained. So, I don't like the knock, it's there and it's not cool. I noticed it but no one else dose. I would say the reason Nissan continues producing the engines with the knock is because it just doesn't make a bit of difference whether it knocks or not. If it's not broke, don't fix it.

Bificus99

And they are certainly not going to go to any more lengths to fix these since the 8th Gen is on the horizon.

Richard66

Does the 8th gen come with a new engine design?

Nopike

iTrader: (2)

I'm glad that you are not having any issues but I would say that engine knock is a problem even if the only symptom is noise. I certainly would not want the engine on my new car to sound that way regardless if the engine ever fails or not. Nissan should have taken this very seriously.

CorollaULEV

No one would want their engine to knock, but really, very few people would notice the knock. It is very slightly louder than regular injector tick. I was really worried about it for a good while and after getting the UOA back, obviously it's nothing to worry about. No longer worried about it on my car. Hate anyone else would be because it's just nothing to be concerned about.

Nopike

iTrader: (2)

At least your experience may reassure others that their engine will not blow up due to this issue. The noise may be annoying at worse.

Emoney66

As I sit in the dmv I'm reading all of this and almost all the 7th gens have a "knock" to help with this noise you need to use nissans Ester oil... Just like the 370z the max it's recommend to help with noise..

1996blackmax

iTrader: (2)

I've listened for it several times, but I don't have the noise...I've mainly used Mobil 1.

CorollaULEV

Right idea but wrong engine part. The purpose of Nissan ester oil is not to smooth out the bottom end of the engine. The crank and conrods and bearings are same as any other. However Nissan utilized a DLC or diamond-like coating on the valvetrain on the VQ35DE, QR25DE and VQ37VHR. It is a smoother and slicker coating on the cam lobes and cam followers to reduce valvetrain friction. The benefit of using Nissan ester oil is that ester is chemically attracted to the DLC. It is supposed to further reduce friction in the top of the engine. I used it on one oil change several years ago, noticed no difference. Otherwise, I have always used a high quality synthetic and at 145,000 mi now, have always had good luck and good wear as you can see.

I might give it another whirl to see if it makes any difference, but the stuff is so darn expensive. Supposedly the real benefit is better fuel mileage and a few extra hp.