Hissing clutch noise
 

Hi,

When I cold start my car this morning, my clutch is making a hissing sound when I press and release, and it is gone after the car is warm up.
Is it a problem i should concern or it is normal because of the cold weather?


Thanks

Oh, maybe the clutch parts (TOB) and transmission are just getting warmed up.

I wouldn't worry about it unless it gets worse.


humfrz

Can you make a recording?

Does it hiss when your foot is off of the clutch, or when you are pressing it?

Yea it just happened this morning between 1C-5C

It only happen when press and depress, its gone when my foot completely off the pedal.
Also, its gone like 5-10mins after driving.

Is it more like a "squeak" than a "hiss" ... ??

Squeak, like an old rusty spring ... ??


humfrz

I am pretty sure its hissing noise, its like air leaking sound.

Do you mean as you are moving the clutch pedal?

Yes!

Wow! Ok, I've never heard that.

Check your clutch fluid level in the reservoir. I can only make a crazy guess. that it might be air bubbles being forced through the small orifices in the master cylinder/clutch delay valve.

Hopefully someone else will recognize the symptom.

What can I do at this point =[ ? I search alot on google and i cant find answer.
add fluid clutch? ignore it? normal in cold weather?

sad

Well, to follow up on what @Ultramaroon mentioned, first check the fluid level.

If it is up to the full mark, you may consider bleeding the clutch system to rid it of any air.

But, like I mentioned before .....I wouldn't go messing with it (other than bleeding the system) unless it gets worse.


humfrz

Impossible to know. What color is your clutch fluid? Is it nice pretty yellow?

Like @humfrz said, if the reservoir is full just give it time to feel/listen for it to get worse.

Things to watch:
1. Extra pedal resistance. If it feels like it's binding then be careful to not break the clutch fork.

2. Trouble getting into gear. If the pedal feels mushy and you have trouble getting it into gear then there is air getting into the system. The only way that happens is by completely draining the fluid from the reservoir. Watch the level carefully.

Mine is doing the same. Haven't though about old fluid. Might try a new stuff.
I was thinking it could be the TOB. But is been shifting fine since it began in the summer.

Yep, new brake fluid is a good idea, especially if it has been overheated (usually by track use) or it's old. Brake fluid is hygroscopic and if it absorbs water and the water freezes, a hydraulic clutch system can act all wonky.

Ahhhh.......yes, back-in-the-day, as several remember, just use two 9\16th inch wrenches and adjust the clutch linkage. Have we made progress or what .... :rolleyes:


humfrz

Its hard to put in reverse and first gear in the morning cold start@@ not sure if its related to it,,after the car is warm up its fine. The clutch fluid is between yellow to brown, I ll bleed clutch during weekend and see what sup.

Thanks

My guess is the TOB as well...

With the clutch depressed, does the "hissing" sound like water flowing through pipes?

One big detail is missing, does this sound occur only when the engine is running?

If the problem is isolated to the hydraulic mechanism, then the sound should also occur when the engine is off as this is an independent system. (I agree bleeding this system every couple years is still recommended).

If the sound occurs only when the engine is running, it might be related to the throw out bearing. This bearing is only loaded when the clutch pedal is depressed, and will only make noise when its spinning.

It could also be the clutch fork, when you operate the clutch pedal, you can see the slave cylinder pushrod extending and retracting to move the top of the fork, these surfaces may be dry or something. Something in my own clutch system squeaks when I move the pedal and I suspect it's this interface, but I haven't been concerned enough with it to investigate it yet.

Ooo, VERY good point!

On yours, the main pivot is dry.

The guys have it covered so I will just leave this here and stroll away.


https://i.ytimg.com/vi/rF7qddSwvdA/maxresdefault.jpg

That's what I suspected. You think it's the main pivot inside the bell housing? Any ideas on how to service it without having to perform a transectomy?

watch out for an RKO outta nowhere

If you pull the boot (gotta pull the slave cyl) you can get a dab in there with your finger/screwdriver. Jiggle and repeat.

Yes, the sound only happen when the engine is running.
if its the TOB,,then i am fk ...

so frustrating looking for the problem....all problem occurs start when winter comes...

Yes,, it sound similar to that! But its gone after the car is gone, let say 5-10mins

Man, I dont think the dealership will do that since its too much work and no direct evident...

If it's the TOB then it will only get worse over time. Just don't take the car on any long trips. @wheelhaus nailed it. If the sound only happens when the engine is running then it's most likely the TOB.

If the noise remains present while the clutch pedal is held down (not just while moving in or out), then yeah it's very likely a TOB. Bearings will sound "dry" when they start to go, so the "water running through pipes" description is actually the raw rolling or scraping noise of the bearing thats resonating through the bell housing. The noise going away after some time could be some minute amount of remaining lubrication finally warming up and coating the races. Definitely get it replaced before it grenades!

Keep your eyes/ears on this. If it starts to get worse, be prepared to get the TOB replaced. Mine was noisy for a while, but then suddenly got worse and self destructed. This also doesn't seem to be that unusual, there a re a fair number of others here reported same problem at around 50,000 miles.

My throw out bearing seized at 32k

How many miles between first noticing something odd, and meltdown?

300 miles maybe. I was driving the BRZ home then the bearing started screaming and lots of smoke. I was hoping it would last until winter but that didn't happen.. I just give me more time to redo some body work before spring.

Wow, that was quick. Guess that's a warning for the rest of us.

Don't ignore it. :/