Hi All,

Driving a 07 G35x Auto.

Noticed a slight rattle on hard acceleration, sounds almost like metal plate shaking when RPM's get high and its usually right before the Auto kicks from first to second gear.

Anyone experienced this issue or have any thoughts on whether or not it is worthy of mention to the mechanic.

Thanks,

 

iv read a few ppl complain about that at redline but have not really experienced anything like that, if there is any slight sound then its hard to hear at all with my intakes and exhaust sounds.

 

Are you running premium? Kinda sounds like spark knock / pinging.

 

No, u r COMPLETELY safe.... my 08 rattles under hard acceleration, I had a thread on this a while back and others said the same thing. I had 2 loaners so far (09 and 11) and they rattle even worse than my 08 when I floor it... dammed if I know why Infiniti designed the car this way. Its not the gears or the engine... most likely a heatshield or something.

 

Run premium fuel at least a 91 octane
This engine has a compression ratio of 10.6 to 1 on 2007 and newer, this is up from 10.3 to 1 on 2005/2006 models. the knock sensor will only respond on mild engine loads pulling at highway speeds not quick exhilaration's.

 

Engine rattle or knock is never good, this is when you need to get out of the
throttle. >>>> To all a good night !

 

I think the op wasn't referring to engine knock... or was he? I have a rattle and I always use premium

 

I had a rattle on start up. have had this problem on other cars. traced it down quickly to the dealer installed oil filter....FRAM....(printed on outside of can mfg by Fram) and in large letters NISSAN...Fram uses a cardboard check valve allowing any oil held in suspension to drain back into your crankcase causing DRY startup...I wonder sometimes if there is any wear on rodbearing when so many people are now using 0-W-10 wt oil or 5-W-30. Knowing that if it is dino oil the zero wt is also the high number when all of the viscosity improvers burn away after a few thousand miles. I did much reading on OIL with much direction to FILM Strength and FILM thickness...people that build engines have a lot to say about this because with stock engines the clearance is so small it leaves very little for an engine winding high RPM

 

This is the issue with noises when we try to figure what's going on with another members ride. Is it a rattle or knock? Rattle could be anything that's loose but that should occur at cold idle too. A knock is most likely poor quality gas or wrong octane. When was the last time you changed your oil or check the level?
Gary

 

I have this rattle too at 1-2 and 2-3 upshifts around 4K+ RPM. Drives me crazy and sounds cheap, but the dealer told me it's normal. Just the way the resonators are designed (the small pre-mufflers). I already checked the heatshields and they're secure.

It's the elusive balance between sport and luxury. Sport = Loud. Luxury = Quiet. It's hard to get it right (though BMW seems to do it pretty well).

Design issue, not a problem. But if there's a fix I'm listening.

 

Could it be the timing chain/tensioner?

Or, try looking under the car and see if any part of your exhaust is getting too close to the heat shields. If so, bend the heat shields back as far as you can. Both inspection and fix is better accomplished by being completely under the car (Safely held up by jacks or a lift) so you can shake things up a bit to mimic movement.

 

Ummm from what I have seen, all g35 and g37s have a rattle under hard acceleration ..... it doesn't seem like an engine knock

 

I have had my 08 for a few weeks and this exact issue has been the biggest annoyance I have with the car. It sounds cheap or like there is a leak in the exhaust system somewhere. I have no emissions laws where I live, so I am tempted to do a custom big pipe exhaust system. I am worried about sound, I don't want any load drone, but I want to hear it when I step on it. I am kinda scared to do anything.

 

Uhm...mine doesn't.

 

^ I don't have a rattle either. The first place I would have checked would have been the exhaust shields, they tend to rattle right before the shift occurs at higher rpm's. Do that many people have a rattle during hard acceleration???