First off, relax. I never said I've replaced 30, I said our shop as a whole has probably done around that number. The chain noise is very easy to pick out, it's basically just like the bulletin states. A whine noise when revving the motor cold. I don't recall stating it only lasts 10 seconds, I don't know where you got that from. As a matter of fact, if the chain is stretched enough, the noise is constant and will not go away after any amount of time. I don't know if the chains I'm replacing are a revised version, which I've also previously mentioned. Remember, I didn't design the car, I didn't build the car, I didn't break the car. I just fix it. The majority of them are 2011's, I've done a 2014 with 22,000 miles on it though. And your opinion on the motors being different is completely wrong. As a matter of fact, the same parts are ordered to replace the chains on a QX56 as they are on an M56. I'm sorry you don't think they "look" similar. We do mostly QX56's simply because they're more common, at least around here. There's not too many M56's. And since in your experience Infiniti TSB's are very specific and make no mention of the M56, you're wrong again.reggiebrown40 wrote:Blackcat81, you say that you've replaced 30 or more QX56 timing chains and only ONE M56/Q70 5.6 timing chain. How can you say that the issue is with all 5.6 motors? What model years are you replacing?. Also, the QX56's motor looks nothing like the M56's from what I can see, so I'm willing to bet they are very different. From my past experience Infiniti TSB's are VERY specific in that they include all models affected. the TSB that was posted at no point references the M56. The TSB for the QX56 is below:
-REVISED-
2011-2013 INFINITI QX56; WHINE NOISE FROM ENGINE AREA
A whine type noise is coming from the Bank 2 (B2) side of the timing chain system.
• The noise is best heard from the high pressure fuel pump area.
• The noise should increase in frequency with engine speed (RPM).
• If the noise does not increase with engine speed, the timing chain system may not be the cause.
Refer to the appropriate section of the Electronic Service Manual (ESM) for further diagnosis.
Also, your posts state that if you hear the whine for 15 seconds during a cold start up that it's the timing chain. Then in another post you say it may not be the chain if it whines. I'm confused because the information you're giving is very conflicted. Several members of the board have the exact same issue for their M56's and 1 or 2 have had the timing chain replaced (CRV_33 comes to mind) and STILL have the whine. Based on your last post, how is this possible?
I've researched by googling QX56 whine and I find that most complain that the whine lasts for 10 MINUTES, not 15 seconds.
Are you replacing the QX56's with a newly designed timing chain or the exact same one as before? If it's not a newly designed timing chain, how can you say that it won't fail again as early as 20K miles?
I just need to get some consistent information here. I'm going to the dealership in 2 hours and I'm going to cold start a new Q70 5.6 to see if the problem still exists if possible. Too much inconsistent information is being posted and is causing widespread panic IMO.
My goal isn't to cause widespread panic, as a matter of fact I think you're doing more of it by putting words in my mouth and posting misinformation. I don't know what to tell you. I work on them on a daily basis. Will EVERY one have issues? I doubt it. Do a lot of them? Yes. I've also mentioned previously that every one I've done, or that our shop has done, has been done under warranty. And I'll say it again, they're amazing cars. The timing chain issue wouldn't deter me for a second from buying one. I'm not trying to steer people away from them, I actually can't speak highly enough about how great they are. I can just post what I see when I go to work. If it's bothering people, I can stop offering advice and help, either way I won't lose any sleep over it.