Ok, I posted a while ago about the same issue, however, the sound has gotten worse. I have no idea where this is coming from, I can't tell. I can tell you that while listening the exhaust at the back, I could hear it from the exhaust too.

Here is the video, You can clearly hear it towards the end of the video. At the beginning it is kind of noisy.

VIDEO0014.mp4 video by diyar21 - Photobucket

Any ideas??

Thank you.

 

My first thought is a damaged valve(s)......

 

hey nice to see you post musclefan! maybe time for that V8 upgrade!

 

OMG musclefan, that sounds real bad. Have you taken off the valve covers? Checked the oil for debris? I do not think I would be running this motor anymore until I found out what is making that horrible noise.

 

I wonder if it's a timing chain being loose. How many miles do you have on it?

 

I was researching the VQ engine and your engine sounds like it needs valvetrain / head work on it.

Here are some video's from teh VQ35DE engine V6 and should help with diagnosing the sounds.

YouTube - Knocking on Nissan Maxima (1)

YouTube - Knocking on Nissan Maxima (2)

YouTube - Knock on Nissan Maxima (3)

KNOCKING REVEALED

YouTube - Knocking revealed on Nissan Maxima

Rocker arm damage or something of that sort



REVING ROCKER ARMS





Urgent Help need valvetrain chatter and tapping...Maybe TDI?? - G35Driver

 

thank you guys. I forgot to mention, as soos as i give it gas (even barely) sound goes away. She becomes smooth. No knocking, etc. While driving. No hesitation. Driveability is smooth as usual. She has 55k on her now.

Do you guys think winters brutual cold weather caused this? This happened in the middle of winter. I suspected that, my gf drove her while the engine was ice cold, went kept the rpms a bit high. What do you think?

 

I thought you sold that one to your girlfriend......might be time to get a new girlfriend???

 

It sounds like an alternator bearing. When you rev the engine the belt tightens enough to quiet the bearing.

 

Hmmm. That's odd because at speed then the knocking if a valve issue should I'd expect to be magnified. The timing chain though might get tighter at speed due to force, just a thought. I really don't think it's the winter muscle. Our winters not that cold. Something I think is loose somewhere, check all the belts/ what about the pulleys, like the alternator etc? anything that could be clanking on something else?

 

I tend to agree. Alterntor or a pulley rubbing something.

I get the same sound if my CIA comes loose and touches the Serpentine belt.

The fact that he has no loss of drivability suggests something simple. Outside the engine.

roadster with a stick

 

Water pump bearing.

 

Quote:

Water pump bearing.

I was thinking same thing in terms of bad bearings....don't know about the pump suggestion, but bad bearings would explain the noise disappearing when throttled.

 

Remove the belt and fire it up! If the noise goes away, It's not your motor. Takes all of five minutes to do and calm your fears about the motor being shot.

 

brilliant idea silver. The most obvious is usually the smartest. Good call.

 

With the belt off you can check all the pulley bearings.

 

I would also place my bet on a bad bearing, or loose pulley. The high frequency of chatter makes me think that its something spinning faster then the engines regular 600rpm idle. You can hear the normal valve click in the background about 3-4 clicks a second. And the loud grinding noise is much more frequent then that.

 

If you don't have an engine stethoscope here is a trick used by technicians. You take a long 3/8" extention, as long as you can get. I have a 3' extension. Put one end actually resting in your ear and place the other end around the engine listening for the point the noise is the loudest. You may not pinpoint the exact problem but it puts you in the area to investigate.

Hope this helps. Let us know what you find.

xfirepop

 

Just don't get too close to the moving parts or you will be like Van Gogh.

 

Get a mechanic's stethoscope and start probing, you can't make any assumptions from where this is coming from.