I've had the car since August last year. No real issues with it so far
But this sound started about 13 days ago.
I don't know the status of any aftermarket parts or upgrades in the car so can't answer any questions as to what parts it has in it.

When it's accelerating between 2-3k rpm and when you let off the accelerator it has this super loud tapping noise similar to a low oil sound only loud as.

If I fully depress the clutch it stops. And on higher rpms it either goes away or is intermittent.

I haven't a clue where to start in looking for what's going on except maybe it's transmission related? 🤷


​​​​I can upload a video if anyone wants to hear it and can help a girl out.

 

A video might help. By the sound of it, it could be the throw out bearing or the previous owner may have installed a single mass/lightweight flywheel.

Do you hear the noise at idle and when you depress the clutch it goes away? Under load in a higher gear at low rpms (ex. 3rd gear at 20 mph) do you hear the noise and as revs increase with increasing speed, the noise disappears? If yes to both, then that would point to a lightweight flywheel and that's normal.

But since this noise just started 13 days ago, that would lead me to believe it's a consumable item like the TO bearing. Or maybe even the clutch. Have you noticed any slipping?

 

It doesn't do it at idle and the noise only disappears above 3k rpm. Gear doesn't seem to matter. But also can be heard intermittently while higher revs. It's so random because it comes and goes. I'll see if I can convert my video and upload it.

 

Let me know if this works or not.

 

Ewww. That doesn't sound good.

Paging my350z internet sound doctor @icer5160 to see if he can diagnose...

 

You rang!?

Hello Ic3,

Tell me, do you feel excessive vibration coming through the shift ****? Does the car feel down on power at all? Aside from the new noise, does the car still drive/feel the same?

If you're still running with the OEM clutch and flywheel, then there's a chance the OEM dual mass flywheel is worn out or the clutch disc itself (or both). Both the OEM disc and flywheel use a system of springs to absorb shock/vibrations from the crank (torsional vibration). If those springs or hinges have worn out, that would negatively impact the balance of the rotating assembly. When connected to your transmission (clutch pedal released), the vibration would be subdued from the added rotational mass of the gearbox and drivetrain. When disconnected from your input shaft (clutch pedal pressed down), the noise level increases. I believe the same is true when applying & removing torque (throttle) when in gear. Apply throttle and noise level reduces, release throttle noise level increases. Fingers crossed your transmission input shaft bearing isn't shot.

I would still have a professional look at the car and give their diagnosis. But right now I'm leaning towards a worn out clutch/FW and/or throw-out bearing. The OEM parts are outrageously expensive, so I would recommend a single-mass aftermarket flywheel and clutch combo. If you want to keep the factory sound & feel go with a heavier flywheel (18lbs+). Something like THIS . I'm personally running this clutch kit (which includes the throw-out bearing), and I love it. Very quiet, very smooth, and less drivetrain slop vs. the OEM dual-mass setup.
Good Luck!
-Icer

 

You guys are gonna laugh.
It was low oil.
My dipstick was showing that there was enough oil on there the first couple of times I checked it but for what ever reason it doesn't ever read properly (oil above the measurement section and not in the measurement section etc)
So I chucked a litre and a half in there and lo and behold the noise stopped.

I feel so dumb because on every other car I've ever had it taps on idle if the oil is low. Honestly.

Anyway moving forward I'm thinking I might get an oil level gauge instead so we never have this problem again.

 

Hi Ic3,

I did think that the noise was timing chain slap for a minute. But your comment about the noise not present at idle and also that it comes and goes with the clutch pedal actuation, ruled that out for me. Btw, I don't think your Z is an 06, I'm guessing it's a 2005? The RPM gauge should redline at 7k if it's an 06 6MT with the Revup VQ35DE, but yours redlines at 6600RPM, which is for the 03-05 standard VQ35DEs. Anyways, you can help mitigate some of the oil consumption by switching to a 40 weight. Check your oil level every other fill up at the pump or at least once per month.

It's always been a bit of a pain to check oil level on these engines. The dipstick tube is in a hard to see location and has some interesting angles to it. Make sure you're on a level surface, engine cold/off preferably. Pull out & wipe clean, dunk the stick until it bottoms out and then re-check. The design of the stick and neck of the tube can cause it to bind up and not fully bottom out sometimes, so make sure you get it 100% seated before pulling out for inspection. Be careful not to overfill, that is worse than being slightly below Full.

I truly hope topping off the oil solves the issue in this case. Clutch jobs aren't terrible on these cars, but it's still a hefty bill when parts and labor are added up. Oil is cheap! So keep an eye on it and just top off as needed. From the Low to Full mark is about 1 quart of oil.
Cheers!
-Icer

 

It's definitely a revup. And registration details say 06 but I'll double check the plate. Maybe Aussie delivered ones are slightly different. Thanks for the tips ☺️

 

The Nissan engineer that designed the dipstick and location in our engines was truly a sadist. If you want a fairly straightforward (and accurate) method of checking the oil, read this thread.