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| Most likely source of bearing squeak type noise?; Replaced timing belt idler as well as water pump | |
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| Tweet Topic Started: Aug 13 2014, 04:34 PM (643 Views) | |
| cwatkin | Aug 13 2014, 04:34 PM Post #1 |
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I am still catching up on maintenance on the new 1992. Most recent work includes replacing the timing belt as well as the idler. I had replaced the water pump earlier and re-used the same old used belt and idler until the new one arrived. A noise like an idler bearing going started up a week or so ago. I figured it was the timing belt idler so get that replaced ASAP when the gates belt kit came. The noise is still there so it wasn't that. I installed a new lifetime warranty water pump so I would guess it isn't this. How often does this happen with the alternator? It is coming from the timing/serpentine belt side of the engine so I would have to guess maybe alternator or I got a bad water pump. Any other suggestions? I do have a spare alternator sitting around and I know that isn't a ton of work but anyone else think I might have overlooked something? Conor |
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| Mythstae | Aug 13 2014, 04:41 PM Post #2 |
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Do you have a mechanic's stethoscope? If not, a really big screwdriver or something? Put one end against what you think is making the noise, and the other end to your ear. I recall we used a crowbar held against the offending part to isolate a noise in Old Man's 'vert. Just, you know... be careful you don't get whatever you're listening with, tangled up in the belts. Be safe and good luck! |
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| cwatkin | Aug 13 2014, 05:43 PM Post #3 |
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I just tried this with a large metal pipe I had laying around. I put it against the alternator, water pump, and transmission with the engine running and could hear a normal rotation type sound but none of this squeak or whatever I have been hearing. I also tried checking for vacuum leaks thinking it was more of a whistling type sound. There might be some coming from the intake port for the IAC under the air cleaner but blocked it off and could still hear it as the engine just barely kept running. I am still not discounting some type of whistle from within another air passage such as the EGR. This is a sound like when a bearing starts to get dry, not a squealing like when a belt is slipping. I had the belt off during the timing belt swap so it was retensioned and sound no different. What else can make this type of sound? Could anything internal to the engine do this? I would expect some type of internal engine bearing or journal such as a main bearing or camshaft journal would make more of a rattle or knock. The engine sounds good besides this. Lifters are normal and it sounds like any other G10 which isn't the quietest engine ever made. Conor |
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| Old Man | Aug 13 2014, 07:26 PM Post #4 |
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With a cold engine I would remove the alternator belt and start the engine. You would then have a very few minutes to raise the hood and listen to see if it is still there. Not there?.........Its in the belt. Still there?..........keep looking. |
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| cwatkin | Aug 13 2014, 07:58 PM Post #5 |
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Ok, I have isolated this to the transmission area. Depress the clutch and the sound goes away. Let off and it comes back. Repeated with great reproduceability several times. I barely touched the clutch and the noise went away. It does it in gear and doesn't sound that much different. I did check the clutch adjustment as I replaced the clutch, pressure plate, throw out bearing, pilot bearing, etc. not that long ago and figured the initial wear in is done. It was a little tight so I backed it off one complete turn. I could tell just touching the adjuster made a difference in the noise. BAcking it off reduced the noise for sure but did not eliminate it. I am starting to wonder if it is more of a vibration than a squeak. The transmission and clutch operate very well. This one has no synchro issues which seems to be a miracle from the others I have driven. I let it roll in neutral and the noise is more pronounced when rolling along a bumpy surface like a gravel road vs. smooth. Is this just a minor annoyance or a sign of impending doom? Conor |
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| cwatkin | Aug 14 2014, 04:27 PM Post #6 |
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Ok, several people have now told me this is probably my throwout bearing. Is it possible to change this without completely pulling the transmission out or not? Can I separate it and get to it or not? I don't remember? I don't remember the brand but it is the one that everyone here suggests. An Asian sounding name if I remember right. Conor |
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| Car Nut | Aug 15 2014, 04:31 AM Post #7 |
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There are two things that are known to be issues that are transmission & bearing related. The first is a throw out bearing & the second is the input shaft bearing on the transmission. Generally on a properly adjusted clutch, you would hear a defective throw out bearing making noise when you just start to apply pressure to the clutch pedal with the engine running. You can actually have it running in neutral & apply pressure to the clutch pedal with your hand, lisrening for a grating noise. No need to fully depress the clutch. Just apply enough pressure to take up the slack in the clutch cable adjustment & see what you hear. The second issue is possibly the input shaft bearing. The bad ones that I've heard are usually noticed when idling in neutral, & foot off of the clutch. When you start to depress the clutch, the noise goes away. To review, Bad throw out bearings usually make noise when slightly pressing on the clutch. Bad input shaft bearing noises tend to go away when slightly pressing on the clutch. Hope that helps you narrow it down. Edited by Car Nut, Aug 15 2014, 04:35 AM.
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| cwatkin | Aug 15 2014, 09:09 AM Post #8 |
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Sounds like input bearing. Will driving it this way do any damage further than the input bearing? Besides this noise, the transmission is smooth and easy to shift. Also, I was curious how big of a deal just changing the input bearing is. Should one do a complete rebuild if they go as far as the input bearing? Would it be a mistake to change the input bearing and nothing else? Conor |
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| Car Nut | Aug 15 2014, 10:11 AM Post #9 |
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Haven't had to do one yet, so can't say for certain. Hopefully David or Murf, or somebody will chime in & let you know. Stay tuned. |
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