Mechanic's Stethoscope - interpreting noises
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Hi all,
So yesterday I spent 5 bucks on a mechanic's stethoscope. Now I am wondering how to interpret the various noises that the stethoscope picks up on our cars.
Holding the stethoscope to the cam cover, I can hear distinct 'clacking' noises that seem to get louder the closer one gets to the fuel injectors. So I am assuming that this is the noise of the fuel injectors firing.
Going further down to the exhaust side of the head, those clacking noises are pretty much gone, and there is just some random background noise.
Does that sound like everythinng is okay? How would I check for wrist pin noises, rod bearing noises etc.? Does anyone have a list of what you need to listen for?
Thanks!
Gary.
So yesterday I spent 5 bucks on a mechanic's stethoscope. Now I am wondering how to interpret the various noises that the stethoscope picks up on our cars.
Holding the stethoscope to the cam cover, I can hear distinct 'clacking' noises that seem to get louder the closer one gets to the fuel injectors. So I am assuming that this is the noise of the fuel injectors firing.
Going further down to the exhaust side of the head, those clacking noises are pretty much gone, and there is just some random background noise.
Does that sound like everythinng is okay? How would I check for wrist pin noises, rod bearing noises etc.? Does anyone have a list of what you need to listen for?
Thanks!
Gary.
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Gary this is a hard one. I've been using a stethoscope for a few years and still can't trust my ears. Use it often and on different items. Eventually you'll get a feel "ear" for what sounds right and wrong. I recently suspected worn bearings in my alternator in my 951. After I removed it, I wasn't certain because the bearings felt ok when spun by hand. Changed them anyway and the noise was gone.
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Thanks Dan for your reply.
It's hard to know though when something sounds "right"... I only have this one 951, so I have really no baseline for comparison...
Anybody else have experience in using a mechanic's stethoscope?
Thanks,
Gary.
It's hard to know though when something sounds "right"... I only have this one 951, so I have really no baseline for comparison...
Anybody else have experience in using a mechanic's stethoscope?
Thanks,
Gary.
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Originally posted by turbite
Gary,
You're welcome to try it on my 951, though it doesnt make too many noises![Wink](https://rennlist.com/forums/images/smilies/wink.gif)
Where'd you get the stethoscope for $5?
Gary,
You're welcome to try it on my 951, though it doesnt make too many noises
![Wink](https://rennlist.com/forums/images/smilies/wink.gif)
Where'd you get the stethoscope for $5?
![Wink](https://rennlist.com/forums/images/smilies/wink.gif)
I got it at Harbor Freight in Newark. Cool place. So many tools to choose from, and very cheap! I also got a nice set of metric wrenches 8 - 19mm for 7.99, and a set of 4 prybars for 6.99. Quality? Well, it's certainly not Snap-on or Hazett, but it seems plenty good for my purposes.
Gary.
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A mechanics stethoscope has its own acoustic transfer function, which unfortunately changes depending on how hard you push. According to my ears it amplifies only the midrange spectrum.
Despair not, it is easily worth a $5 investment and can among other things be used to detect if injectors are working or not (apply it in the axial direction on top of the injector body) and determine if bearings are worn or dry.
Laust
Despair not, it is easily worth a $5 investment and can among other things be used to detect if injectors are working or not (apply it in the axial direction on top of the injector body) and determine if bearings are worn or dry.
Laust
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I did not know there was a Harbor Frieght in Newark. Cool. I use a stethescope every now and then. Not sure I've ever actually found anything with it, other than to confirm that the stock injectors click really loud.
#9
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What the hell are you guys talking about? A mechanics scope is not flat and does not look like one at the doctors office. It has a long metal end (looks like a giant needle of sorts).
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#11
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You'll make yourself crazy listening with that thing. I just use one when I can hear a noise and want to find out where it's coming from. A long screwdriver held to your ear works pretty well too.
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Originally posted by Matt H
What the hell are you guys talking about? A mechanics scope is not flat and does not look like one at the doctors office. It has a long metal end (looks like a giant needle of sorts).
What the hell are you guys talking about? A mechanics scope is not flat and does not look like one at the doctors office. It has a long metal end (looks like a giant needle of sorts).
Well, I was hoping that there are some 'rules of thumb', you know...
Like, "if you hear a clacking noise at the camtower near the injectors, but no noises further down on the side of the head, then your wrist pins, rod bearings, etc. are A-Okay"
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All right, so it appears to be more complicated than that. That's fine. It's still a fascinating tool to play around with.
Thanks,
Gary.
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Yep, neat to mess around with. I kind of agree with Peckster, you can drive yourself nuts. The other real issue is trying to figure out whether a noise is normal or not.
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