Knocking may not be the best way to describe it. But I'll lead with that.

My 06x, 128k miles.

Only when the engine is fully warmed up, do I hear a faint rhythmic knocking noise at idle. Cold engine, immediately after startup and while warming up, you won't hear it. It's best heard from the interior, with everything off. It's probably started noticing this since 70-80k miles. But not that the car Is older, it seems to bother me more as to what it is.

The noise goes away above idle. If I slowly give it gas, it disappears. If I rev the engine, you won't hear it at all. Won't hear it on startup. If the engine is hot, you'll hear it once the engine settles down to idle after 10-15 seconds or so.

Except I'm not sure what the cause is? I've googled fuel damper noises, rod noises, cam noises, etc...and no luck finding something similar. It's nowhere as loud as rod knock vids I've seen. I can't even take a video because the noise is too faint.

It sounds like a low-tone knock coming from somewhere in the engine bay. Using a stethoscope and screwdriver I could not locate it inside the engine from the top and as far down the sides as I could reach. I can't tell which side it's on.

I always assumed it was fuel dampers, but I, trying to be sure.

It's really faint. Can't pick it up on video, and you can only hear it in a quiet area or in interior with everything off.

Anybody else hear a faint knocking noise at idle from their interior?

 

I have the same exact problem, took it to my mechanic and he couldnt pin point where the knock was coming from. Hope its not anything serious

 

my mechanic just told me to buy a new engine
did someone figure out what the hell is that?
or anyone knows whereto buy a good engine from?

 

Is there a remote chance that the knocking sound could be coming from the AC compressor? Or even the alternator? Guess I'm still hoping for an easy fix but I noticed the sound seems to go away when the AC clutch engages...
Have any of you guys come up with any other theories?

 

Someone once thought their engine was knocking, but it was a bad belt.

 

If the mechanic can't hear it with a stethoscope, don't worry about it.

 

Is it a knocking noise or the infamous Ticking Noise that get's worst overtime the age of the car which some Infiniti Dealership claim its normal for the VQ to tick...which to me is a line of crap since the motor never ticked when new. My ticking noise happened when I broke 80k.

 

I've kinda just learned to ignore it. I really can only hear it in dead silence with the radio and HVAC off and windows up.

Since i always have the radio on to some point, it's been out of sight, out of mind.

Guess i'm just paranoid since i like to address every squeak, rattle, or issue as they come up.

Almost to 140K miles. Just gonna chalk this up to an older car nuisance issue.