After having multiple opportunities to determine the cause of the sound under my engine; my dad, a coworker, and I have come to the conclusion that it sounds like a bearing-gone-bad.

Here are the symptoms, and I need some advise as to what bearing you guys think it can be:

It starts/stops at random times. I can't make it start or stop at all. It does it at pretty much any speed, but does not do it while ideling. Pressing the clutch in/releasing it does not make it start/stop (Not throwout beating, I don't think).

I haven't noticed any detrimental effects...yet. I don't have any shaking of my wheel or anything. I just recently (About 4 months ago) replaced my passenger side CV, and am not sure when the drivers side was replaced last.

Does anyone have any ideas as to what bearing/part it could be? Since the noise does not stop/change when I press the clutch, I have pretty much ruled out the throwout bearing...but I could be wrong...

jB

 

The trow-out bearing would stop making noise when you press on the clutch pedal.

As for your bearing,well,you may need to be more specific about where the noise is coming from(Left side,right side),when you hear it(Cold,warm,accelerating....)

I'm not flamming.
Just need more input.

 

I am having a hard time determing which side it is coming from. I think it's coming from the drivers side, but the sound is so loud that it could be coming from anywhere under the car. It does it at any time. It will do it while accelerating, decelerating, coasting, clutch in, etc. It's so random, and that's why I'm having such a hard time telling what it is.

jB

 

I think it's your differential bearing, mine was making the same type of noise. But mine was still on jack stand and at first I thought it was the throwout bearing but took it apart and it was fine. So I took the tranny apart and the differential bearing to the right axle was bad. It doesn't spin as smooth as the other bearing. Replaced that and fixed the noise issue.

 

no, a bad throwout bearing makes noise when the clutch pedal is engaged. it doesn't make noise when you don't engage the clutch.

 

Try using a screw driver or short peice of hose. Placing the flat end of the screw driver, or a open end of the hose. On different location on the engine and tranny. Then putting your ear against the handle, or the other open end of the hose, and listen. Get a longer screw driver, to reach in those hard to get too places...

 

what does the sound sound like?

ticking?
knocking?
tapping?
rattling?
does it follow engine rpm?
vehicle speed?

 

Quote:The trow-out bearing would stop making noise when you press on the clutch pedal.
You are thinking of when the mainshaft bearings go inside teh tranny. At a stationary position you press the clutch in and the grinding bearing noise gopes away. I have never seen diff bearings go before Mainshaft bearings due to the size of them and the way they stick further down in the oil within the case. Anyhow if any of your bearings are whack then I would replace them as a set within the tranny.

 

Just replaced all the bearings in the transmission. The guys at Flamingo Automotive here in Austin told me that before I rebuilt the tranny, I could wait until I had to turn up the volume on my stereo to drown out the sound of the "buzzing" to do so. Sometimes I would start out in first gear and it would be smooth until I hit a certain rpm before the "buzzing" would start. Then it seemed to get softer in second gear and I hardly ever heard it in 3rd-5th. But downshifting from 3rd to 2nd really made a loud "buzzing" noise. They showed me the bearing doing the moise and it was amazing how you can barely feel the nick or flat spot, but it sure makes a lot of noise. Anyway, I fixed the CRX and bought a '90 Civic Si with the same problem, but since I have the two at the same time for now, they told me to see how far I can take this one before it gets unbearable. I've already got a replacement tranny just in case.

 

It's kind of like the sound of a chain tapping against metal/road. Kind of a rattling, or kind of like what "squeekers" sound like against a rotor. It comes and goes at random times while moving. It doesn't follow RPM or vehicle speed, but it doesn't do it while stopped. Pressing the clutch, accelerator, or brakes when it does it will not make it stop. It sometimes goes away when I hit a bump, or just for no reason at all. I can't make it do it, and that's what's frustrating. If I could press the clutch and make it do it, then I would know it's something to do with the clutch, etc... It has no set pattern, and I can see no reason that would make it start stop; and that's why I'm thinking it might be a wheel bearing. The car has 170k on it, and I am not sure if it has ever been changed. Since it only does it when moving, I would think that the wheel bearing (other than the throwout) would be the only thing doing something different than if the car was sitting still (spinning on the shaft). I picked up a wheel bearing today, freaking $45 from Autozone. Does anyone have the helms info on changing it that they could scan in for me? My Chilton is at a friends house, and the Haynes sux..plus I can't find it right now either.

jB