08 sedan rattling engine noise - exhaust shield?

[greg_atlanta]

I'm getting a slight rattling or buzzing sound from the engine under heavy acceleration. Car has 2500 miles and it only happens when the car is in gear, I cannot reproduce it revving the engine in neutral.

I've heard this engine is known to be noisy, but it sounds a little like the buzzing noise I was getting on my 92 Q45 before I removed the exhaust shield covering the cats. I have not spent any time looking under the G on a lift, so can someone tell me if the exhaust has any shields or other parts which are known to be noisy?

It may be just a normal noise from the timing chain or valves - the old Q is better insulated, I think. I'm scheduled for my first oil change next week, so I want to know if there's anything the dealer should check for.

Thanks


Modified by greg_atlanta at 11:56 AM 11/16/2008

[Jacko3]

Sounds like the G-37 issue that requires reflashing of the ECU and the use of Nissan Ester Oil. Stevethetech, awdjdmtalon, will chime in soon to help you out.

[fbpem1]

Sounds like the G-37 issue that requires reflashing of the ECU and the use of Nissan Ester Oil. Stevethetech, awdjdmtalon, will chime in soon to help you out.

noooooo different motor totally.

Also the 3.7 tick is usually at idle you hear it the most.

Might actually be a tsb related issue which requires backflushing of the heater core to fix. I would take it to the dealer since the car is so new but thats probably what it is i have had a few of them do it ranging from EX to the G. Simple fix but the dealer should do it. Also if you wouldn't mind it would be much easier to figure it out if i could hear the noise could you post a sound clip or a vid?

Then agian it could be totally normal i would have to hear it to be 100% certian. since the motors are sort of loud at least the HR which you have.
Modified by fbpem1 at 9:39 AM 11/14/2008

[greg_atlanta]

Might actually be a tsb related issue which requires backflushing of the heater core to fix........ Also if you wouldn't mind it would be much easier to figure it out if i could hear the noise could you post a sound clip or a vid?

Thanks,...... the sound is so subtle I doubt I could capture it on a sound clip, but will try....

I have a feeling it will be considered "normal".

Can you explain the heater core thing? I found the TSB, but I can't see how debris in the coolant could cause this kind of noise. Does it affect the water pump? It's not a tapping noise at all.

from http://www.infiniti-techinfo.com

ITB07007

* IF YOU CONFIRM A tapping noise coming from the dash area when the engine is running at operating temperature, DETERMINE IF The noise is coming from inside the heater core. ACTION "Back-Flush" the heater core to remove gray silicone debris. See this bulletin for further detail.

[fbpem1]

it does create a tapping noise from the debris hitting the sides of it just trust me on that lol. No it won't effect the water pump.

[greg_atlanta]

See if this helps. It's 3 acceleration runs, you can hear it best in the 3rd run (but it's subtle).

Maybe the 1st oil change will help? Dealer uses Pennzoil syn blend, will use that for a few changes and go to full syn around 10K miles.

http://www.youtube.com/watch?v=6ut_Vf_sIBo

[Tampa G35 Sedan 6MT]

I didn't hear anything from the norm... THe techs will be able to help you better!

My question is why haven't you taken it to the Dealer yet?

DJ

[zozoka1212]

I never had rattling noise in my G's.

Hope they will fix yours.

zozo

[greg_atlanta]

One more try.....

http://www.youtube.com/watch?v=y5Z3BPL49OI

I'll be at the dealer friday for an oil change, but since this is sporadic I'm not sure they'll be able to reproduce the sound. It may be normal since this engine is known to be a little noisy.

[greg_atlanta]

Dealer didn't find anything wrong during oil change (but I doubt they spent much time looking at it).

I've decided it's normal, have read elsewhere of VQ35HR owners (G and Z) having the same noise. It's just the way the intake and/or exhaust is designed. I hear it at higher RPMs on 1-2 & 2-3 upshifts.

Still bugs me... it sounds cheap and tinny.

(Exhaust shield could be an issue down the road, but not likely with a new car)

[jefftoney]

I have an 08 G37S which appears to have had the same problem. My problem went away when the dealer replaced the muffler.