guy from norcal

iTrader: (2)

Mine def comes from the front of the car.

Superjay

I had a very similar sound about 6 months ago. Under normal acceleration I only heard it, but under hard acceleration it would bog down. It ended up being a spun bearing on the water pump. Also, since it was the chain making the noise, you may want to check your chain guides. They are essentially designed to go bad at about 60k.

Victory

my chain and chain guides are new and i don't get any bogging, but i still get the noise

Superjay

when you changed the chain and guides did you change the water pump? They're, like, $40, and since you're already in there you may as well do it.

as for the noise, I'm in for when you finally find out what it is

Victory

No, it was all done by the dealership when they did the rear timing cover gasket, meaning it would have been removed and inspected at that time.

The water pump spins regardless of what you are doing, so it should also make this noise when you rev in park or under any number of other situations, which it does not. Any noise from the timing chain would be present most of the time

Weilun Sun

hey guys
i think its about "Carbon deposition"
last week i add "LIQUI MOLY VALVE CLEAN" at first it doesnt make any differents
but next day after 20~40km it reduce that noise Significant
so i decide using additive repeatedly until next maintenance
and i already reservation piston carbon remover and cleaner next maintenance
ill let you all know

Victory

That would point to a knock issue, but the noise itself is so intermittent that it's hard to tell what does and does not help fix it. I removed a stick from a heatshield and didn't hear it for weeks and thought i solved the mystery. Then it comes back, then it disappears again.

I also use top tier 93 octane gas almost exclusively and toss a bottle of similar cleaner in every other oil change. Should be squeaky clean. still get it every so often.

Weilun Sun

do u have picture about that stick
thanks

Kris9884

iTrader: (3)

Just checking in. I spent almost an hour on an undeveloped neighborhood street with a buddy and I taking turns stopping/driving the car and standing outside trying to re create the issue and never made the sound. Then, this morning I heard it leaving the gym. I don't get it. I'm gonna mount a GoPro under the hood and see what happens.

Weilun Sun

:idea: .....

Weilun Sun

any news?

BioG37

Are you guys all able to feel it at all when the noise occurs? For example, car shuddering (even if it's just slight)?
Or is it purely just a noise that you're hearing?
Any performance drain or drag when the noise is occurring?
Has anyone run any live scans (feature on some OBDII scanners) while the noise is occurring, and noticed anything particularly different?

Too bad there's no tool or device out there (certainly at least not one that I've ever heard of) that we can buy to triangulate sounds. On the G37's it'd be pretty easy since we have clean mountable surfaces.
You could mount 1 sensor on the Brake Fluid cover, another 1 sensor on the Battery Cover, and another 1 sensor towards the front-middle (this one of course would need to be the most heat resistant). In this way the sounds received by the 3 respective sensors could be easily calculated to pinpoint ~where the sound is actually coming from (ex: if it's where the Transmission is, or the Engine - both completely different!).
The sensors, if they had two receivers (top, bottom) could even pinpoint it further 3-dimensionally, making it even MORE precise - ex: if it's towards the TOP of the Engine specifically (eg. Camshaft), the Bottom of it (eg. Crankshaft), "Left" (opposite end of Transmission, eg. Timing Belt), etc.


Regards,
- BioG37

Eugenius

I hear the same noise since September. At first i thought who is driving a rusty bucket, but later on i figured out it was me, and my car making the noise.
my car is only 69k and it's pretty disappointing. Also the car is producing another rattling noise from the heating core, which is different noise. Darn my car rattkes from front and rear. Time to get rid of it?

vq37_

I've had the same noise for a while but only when its super cold out, my guess is that its coming from somewhere near the brakes

Kris9884

iTrader: (3)

I haven't started my car in weeks, maybe when it gets above 30 degrees I'll get under there and feel around. I have no idea.