Not to bump an old thread but I remember someone made or attached over the ear / cup head phones to their stethoscope... does anyone by chance know who did this or have a picture? I tried finding it but couldn't source it. Seemed like an AWESOME mod to do considering the ones I have now hurt your inner ear after 1 minute of use.... it's awful pain.
EDIT: FOUND IT: props to Jeremy V
"One tool that I made that I really love is a stethoscope and earmuff combination out of harbor freight stuff. I purchased the standard couple dollar orange harbor freight earmuffs and drilled a hole in each one so that the stethoscope could fit into each of the ear cups and still rest on my ears while wearing the muffs. That way I can get a boost in sound from the stethoscope and also deaden the sound of the running engine etc. to make it more effective. I got the stethoscope from harbor freight also, and I think the whole setup cost me less than $10 plus about 10 minutes of my time.
I second the IR temp gun recommendation especially for things like wheel bearings, differential bearings, and other harder to physically access bearings. Bearings will start to run hot when they get low on lube often without making any extra noise, so an IR thermometer is a better preventative maintenance tool than a stethoscope in my opinion. For something like wheel bearings, I just take a test temp between all 4 wheels after driving a while and if one is noticeably higher in temp then it needs to be looked at, lubed, etc. Also sometimes it can be awkward using just a stethoscope on an alternator or electric motor that uses brushes. The scraping sound of the brushes on the commutator can easily transfer to at least the rear shaft bearing (that is usually right next to the brushes) and make a good bearing sound like it is dry or about to go out, but the temp gun can help you to verify if there really is a problem or not."
Thanks,
-Nigel
TCR out.