This is a problem and a solution.
The noise started about 6mo after I replaced my clutch. Every now and then I'd get a chirping noise after the clutch pedal was released. The noise got louder and more frequent and now it's constant. Any time the engine is running and the clutch pedal is fully released I get a noise that sounds like chirping or crickets under the hood. Sounds like it's coming from the engine.
If I push the pedal slightly then the noise gets louder, and by the time I've pushed the pedal in by 1" the sound goes away. Some days it's louder, some days it's quieter. It's really embarrasing and I find myself hold the clutch pedal in at red lights because the noise is sometimes that loud. Driving through the subdivision I find myself riding the clutch to keep the noise down.
I isolated the sound to the clutch release fork by reaching under the intercooler and pushing the release fork towards the front of the car - sound stopped. Looks like a lack of lubrication on the pivot ball is stopping the release fork from fully releasing the TOB from the clutch fingers - this causes a slight vibration through the release fork that makes the fork move against the pivot ball. The point where the pivot ball meets the release fork is also prone to sqeaking becuase the movement is not smooth. As the engine runs the constant vibration of the squeaky joint translates to a chirping noise.
Today I did the following (after removing the intercooler):
1) Removed the rubber boot around the release fork and attempted to get some grease on the pivot ball joint in the middle of the clutch fork. There is some rust in there, but there was not enough room to get grease in the joint. I put some grease around it and hoped it would wick in there over time. I'm not holding out much hope. The boot was pretty easy to put back - I just had to use a flat-bladed screwdriver to tuck in the flap at the leading edge of the hole (closest to the slave cylinder)
2) Flushed and bled the clutch fluid. This raised the clutch engagement point by about an inch. It was abnormally low to begin with (lower than before the clutch replacement)
Started it back up - noise still there.
3) I added a spring to pull the release fork back toward the slave cylinder. There are other threads on this. This fixed it - however the spring tension has to be *just* right - and it has to pull the release fork tight up against the slave cylinder to pull the tob off the clutch fingers, AND allow for the release fork to move normally.
- If the spring does not pull the fork back enough then it will have no effect at all. The noise will still be there.
- If the spring pulls back too hard then it will force the piston back into the slave cylinder. You can tell this is happening because the cluthc pedal will feel very light for the first half of it's travel, then feel very heavy. You will have trouble getting the car into gear. The noise will be gone but the car will be undriveable because even with the pedal pushed all the way into the carpet you'll be right int he middle of the engagement point.
- If the spring is short then the tension may be too much when you push the clutch. Better to go with a longer spring that has at least 3" of travel without damaging the spring. The spring should be at least 3 or 4" long fully coiled so that it has a nice range.
- If you cannot pull the spring open 3" by hand then it's too strong!
- The spring needs to be applying the maximum amount of tension while the clutch pedal is released - so plan on mounting the spring in a way that it's already extended out by an inch even at rest.
I finally used a combination of a couple of springs and adjusted the tension until the noise was gone, but the pedal felt normal.
So now the noise is gone and I'm happy again. I just wanted to get some of these thoughts down so that anyone else who searches for the same symptoms as I had will be able to get it fixed more quickly than I did. I tried about 4 or 5 different spring combinations until I figured out the what workd and what didn't. Bit of a PITA, however much cheaper than the "Pull the tranny and grease the pivot ball" approach that Subaru said was the only fix.