kukudm

Hi, I need some help diagnose this high pitch whine noise that I have.

Sound clip: https://youtu.be/PYFkEdE3ZiA

Symptom:

After driving 10 to 15 freeway miles, When I let go of throttle at 70mph, there will be a high-pitched whine noise, sounds like "whooooooo". It resembles the sound of the engine winding down. Example: the sound of the engine when we come to a stop, there is a moment where the engine will make a sound that sounds like a wind noise: "whoooooo". In my case, the noise I hear is a consistent, same pitch - "whoooooo"

I can hear it very faintly on-throttle at 70mph (I had to try very hard to hear it due to the engine sound). But off-throttle at 70 mph going down, it is the most noticeable. And it mostly disappears at around 60 mph or below.

When the car is not "hot enough", I won't hear the noise. I live less than 2 miles away from a freeway entrance. When I first get on the freeway from a cold start, I will not hear the noise. It came out after 10 to 15 miles on the freeway.

Clutching in (clutch completely depressed) at 70 mph, it goes away. Gear in neutral, it also goes away.


My car info/history:

- 2007 AP2, all stock, 51000 miles
- Tranny & diff fluid done in less than a day. Amsoil 75w-110, Honda MTF
- Valve adjustment done 2 weeks ago, with new NGK spark plugs
- Coolant flushed 2 weeks ago
- New clutch master and slave installed 1 month ago. Using ATE dot4 fluid.
- Clutch engagement point adjusted to somewhere towards middle and clutch fluid bleed 1 day ago
- Original clutch disc and pressure plate, never changed
- Stock air box is gutted, new OEM HOnda air filter (green color) installed
- Billman TCT installed
- The cover right in front of radiator was gutted on the air box side by last owner to fit a snorkel
- New serpentine belt


Any input on what noise is this? Thanks in advance!

s2000Junky

Is there a faint wine or rotational scuffing noise when car is at idle - and then goes away when you push the clutch in?

kukudm

I just tried, cant hear at idle, with clutch in or out.

The whine I hear at 70mph usually happens when the car has been driven for a while (fully warmed?). In the morning, I usually won't hear it in the first few minutes of 70mph.

It is a faint whine, slightly high pitched.

s2000Junky

Not much else to go on man with what you have offered, its just going to be grabbing at straws for us on this side of the computer. To me is sounds tranny related. But you passed the first round of test if your findings are accurate.

kukudm

I see, I will try to record a sound clip.

Since you mentioned tranny, it reminds me that I recently replaced a new Clutch master and slave, due to old CMC leaking.

kukudm

I gave another try when the car was warm, yes, I could hear a faint whine or chattering noise at idle, and goes away when I clutched in.

Then, I did some adjustment to the clutch pedal rod. My suspicion was that I had it adjusted too high for higher engagement point when I replaced the CMC, so the clutch was constantly half engaging. After the adjustment, the whine/noise gets less noticeable on freeway, but still can be heard. At idle, I no longer hear the faint whine/noise when I clutched in. I will try some more adjustment to see if this noise will completely go away.

Question: does this sound like a half engaging clutch whine/noise?

s2000Junky

Your clutch adjustment would be unrelated to the trans noise if that's where it is coming from. Either the clutch is engaged or it isn't. But on a separate note, making sure you have the appropriate free play adjustment is crucial to not wearing out your clutch prematurely. You don't want to be riding the clutch disc all the time.

kukudm

Thanks S2000Junky for all you input.

I did a few more things today:
- Bled the clutch
- adjust the rod for engagement point

Now I believe the noise is mostly gone. I guess the noise might be due to I was riding on the clutch (or maybe pressure plate since I didn't smell any clutch burn?) and/or small amount of air in clutch system.

I will do the tranny oil tomorrow. Will report back on the issue

Car Analogy

Noise like you describe, high pitched, at speed, goes away on decel or driveline disengagement, is almost always driveline related. Something from trans back. Trans, diff, etc. Usually some worn bearing or gears in trans or diff.

That it sounds more like its coming from in front points to something like the clutch throw out bearing. Hence the tests at idle, clutch in vs out.

Adjusting clutch wouldnt have much affect on this however. So its odd adjusting clutch would help if this is your issue.

Its also not likely that this part would go bad in just 50k miles, unless someone liked to hold clutch pedal down at traffic lights, etc.

Sent from my SM-G920P using IB AutoGroup

kukudm

I can still hear the noise. I guess when I was testing it, I didn't drive the car far enough.

Today I drove it to work, with 15 miles of freeway, and the noise came back.

Like you said, I sometimes completely hold down the clutch while waiting for a light. So maybe the throwout bearing?

I will get the tranny and diff fluid flushed today. So will see after that.