Hello, all!

I'm hoping someone can help identify the cause of the horrible sounds my 2006 INFINITI G35x sedan (VQ35DE 3.5L, non-rev) is making following some transmission (RE5R05A) work I performed recently based on a "AT Check" dash light and P1774 code I was getting for the low coast brake solenoid valve in the transmission. The problem started with rough or hesitant shifting between low gears.

I replaced the low coast brake solenoid with an interchangeable Nachi type solenoid (20-40 ohms), installed a new transmission filter, transmission oil pan, brand new OEM bolts, and refilled with Castrol Transmax ATF/CVT Universal Automatic Transmission Fluid (no leaks). Following this work, the "AT Check" light went off and the car shifted fine, but it developed an intermittent, rapid knocking/tapping sound immediately upon starting the ignition and when accelerating. Video link 1 demonstrates this rapid knocking/tapping sound. I was not able to identify the cause of it.

Fast forward a couple of days. My wife was driving the car a few miles to work and called me because she had to pull over due to the engine (assuming) making loud knocking/squealing sounds, shown in video link 2. I'm not getting any codes, and I have no idea what could be causing the sounds. It sounds like a mixture of rod-knock from a spun rod bearing and a defective pulley, but I have no idea.

Does anyone have an idea of what may be causing these sounds and whether the problem is terminal for the engine? Any input would be greatly appreciated. If I left out any vital information about the issues, please let me know. Thanks, everyone.

Video link 1: Video link 2:

 

Damn! This sounds exactly like my 2002 6 speed manual Maxima did, check it out!

World Famous Nissan VQ35DE Diesel Engine

and yes, i did replace the engine few days later with a junkyard one for $450 and it drove great for another 4 years! I did take the old engine apart but as i'm not an expert, i wasn't able to find out what made that 'diesel' sound.. But now, i believe the piston rings were shot! It did have 212k..

 

MaLPoPies, that sounds exactly like my VQ. Thanks for the upload. I regularly changed the oil on my G35, so whatever is causing the sounds is not from oil starvation. I don't think that sound is due to worn or seized piston rings, but it sounds like you found a solution. Thanks for the reply.

 

Well, i knew the engine was bad before i bought it for $700 and i managed to get a day of driving on it until it ran like a lawn mower engine.. LIke i mentioned above, i didn't really inspect or measure the parts from that engine but seeing all that blue smoke out the exhaust kind of tells me that the rings were not sealing and allowing oil to go into the combustion chamber. As for the squealing and knocking, i'd suspect that the rod bearings retired and piston is having a clap fest with the cylinder head..

 

That's my guess too, but not sure about the stealing. I'm currently working on another full rebuild project and so not sure I want to invest time tearing this VQ completely apart to find the issue(s). If it's not one thing, it's another. Ugh!