ch3tman

Hi all ,

I have recently started hearing a noise that I'd like some advice on. Granted, it is very difficult to diagnose/interpret a noise via a forum, but I''ll do my best to describe it.
I'm aware the humming/hissing induction sound of the S2000 is a normal characteristic - I think I've seen it compared against a Dyson [!] in some forum threads - I don't think this sound is that.

Facts:
- I do not have a supercharger;
- The noise can sometimes be heard faintly on acceleration;
- The noise is more pronounced on deceleration [that is, when letting foot off throttle following strong acceleration]. If accelerating softly, the noise won't be audible when letting off throttle;
- The noise cannot be heard with hood down, only with hood up/windows up/stereo off;
- The noise is so faint my partner in the passenger seat struggles to hear it most of the time I try to point it out!
- The noise is also too faint to be picked up on video;
- The car recently went through its 54k service [oil/filters/diff oil/valve clearances - which required very minimal adjustment - not sure if this is of significance];
- Oil: Castrol Edge 5W-40 A3/B4 , Plugs: NGK PFR7G-11S. All other consumables supplied by Chiswick Honda;
- The airbox lid is on properly - all clips are on securely;
- The sound is audible whether I am in gear or neutral, i.e. I can reproduce the sound if I am
-- 1] in gear --> accelerate & decelerate
-- 2]in neutral --> rev & let off throttle
- The noise is not speed/gear dependant;

Assumptions:
- The noise is coming from front right of car - however it may seem to be the case because of where the drivers seat is. I understand it is easy for sound to propagate around the cabin/engine bay quite easily.
- The sound is not audible from cold start. I have only heard it having driven several miles. However this is not to say it cannot be present on cold start, it's simply the case that I've not heard it from cold.

Other Info:
- Common sense may indicate something in induction/airflow?
- The fact the noise is audible when clutch is engaged or not, I'd like to think, rules out the drivetrain? Not sure...
- The sound can best be described as a mixture of two videos:
-- 1] http://www.youtube.c...2cGBFV2OM#at=24 from 24secs to 32secs
-- 2] http://www.youtube.c...uyPRVcAIE#at=86 from 1min24sec onwards
-- Bear in mind the sound is quite faint and the video's above are the closest similar sounds I can find. The sound is no where near as pronounced is in the NSX video;
- It's the type of noise you'd expect to hear if there was a tiny hole in the airbox, or a tiny gap at the top of a 'closed' window, i.e. air blowing/escaping against a small outlet.


I am very OCD and paranoid when it comes to my cars, hence it could be nothing. But it could be something, and if it is, I'd like to identify and address it...I'd just like to make sure it's of no concern. Hopefully not, as the car still drives perfectly in all aspects, as it did when I first picked it up!

Thanks for reading this far - expertise and advice is much appreciated


EDITED: to bold certain words to emphasise some of the description; else it's easy for others to indicate "I have a similar noise". Does your noise happen under the same circumstances?

Kitesurfer s2000

Diff ??? mine was making a noise for 4 years untill it let go with a bang

Bundle of Mayhem

Sounds like mine which is going in next week for investigation. Mine is louder on a warm engine and I can replicate it upon demand. In the passenger seat you have no problem hearing it. We think it is a transmission noise but will see what Honda say (will let you know).

ch3tman

On what basis/criteria did you arrive to suggesting the diff?

Considering it *seems* like the noise is coming from the front and the noise seems to appear without a gear engaged.
Surely if it's the diff, it would be more apparent when accelerating? I'm not mechanic so I may be misunderstood here.

It'd really like to take a scientific approach to trying to isolate the noise, ruling things out , etc.

ch3tman

Thanks, it would be nice to know what your outcome is.
How do you go about replicating your noise? Can you still do so without being in gear?

Mine is so faint that I can barely hear it, if at all. Hence I'm wondering whether it was always there! But I'd like to be sure...

Bundle of Mayhem

We haven't tried it out of gear but just going out to a BBQ so will try it when we arrive there. Just taken the induction kit off and put the standard air box back on so they can't blame that when they are investigating.

I can replicate it by driving in third gear at 36 miles, fourth gear at 42 miles, fifth at 55 miles and so on. Coming back from London the other weekend and it was constant at 75 and could hear it over the radio.

I know what you mean about hearing noises (but I know this is a new one). I have the same 'rattle' at 2-2.5 revs that other 09 owners have but my local garage say they can't hear it (or won't!). I started to doubt whether I actually had the noise or not at one point as I've lived with it for so long that it's almost standard now.

s2000 gib

I had something similar and turned out to be one of the pulleys! Can't remember which one it was, think it was the crank one but not sure. It came and went and eventually got worse and worse. Sounded like a bird of prey screeching away. Does yours sound similar?

When I took mine off to change it there was some play in the bearing. Since it's been changed, touch wood no problems.

ch3tman

Yours does seem quite different, as it happens at specific speeds in specific gears. That does point to transmission....

As for your rattle, check the exhaust/heatshield for looseness, perhaps..?

Unfortunately it does not sound like a bird screeching at all. It is a very faint whistle like sound.

Dembo

Have you tried turning the fan off? Mine sometimes makes a whilsting noise, which you'll only ever hear with the roof up.

Bundle of Mayhem

Mine doesn't make the noise in neutral. Heatshields all checked previously. Hope you get it sorted.