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Wrenchin’ Wednesday: Three ways to find THAT sound

We’ve all heard it: that sound that just doesn’t match any sample in your head. It seems to come and go on a whim—maybe if everything else was a little bit quieter it would be obvious what’s crying for help beneath the mechanical symphony created by a running engine.

 

That’s where today’s Wrenchin’ Wednesday comes into play. Here are three different ways to diagnose noises and discover problems before they escalate into catastrophic failures.

 

Read the full article on Hagerty.com:

https://www.hagerty.com/media/maintenance-and-tech/wrenchin-wednesday-three-ways-to-find-that-sound/

Replies (18)

Replies (18)

My bodyman's son is in the Air Force and works in the ground crew for C-5 Galaxy transports. The Air Force was ready to ground all the C-5s because the nose wheels were locking up and they didn't know why- but it was dangerous. This young man who grew up working on cars showed them how to jack up the nose wheels and spin them while holding a screwdriver to the hub and to his ear, thus verifying that it had a bad wheel bearing. The hi-tech experts were dumbfounded at this "revelation" and he got an award for saving the taxpayers who-knows how much money. Sometimes the old fashioned basics are the best as mentioned above.

Pit Crew

I have tried most of the variations listed here and they all work well. My favorite is a medical or mechanics stethoscope, but remove the diaphragm and replace it with about two foot of 3/16" or 1/4" steel brake line. It works on mechanical knocking sounds, noisy alternator and water pump bearings, exhaust leaks, and most vacuum leaks.  Plus you can swap a longer piece of brake line, or bend it to shape for tight areas. As always, be careful around moving parts on a running engine. ... Gary

Pit Crew

And then there is using a length of tubing to sync your twin SU carbs by ear.  Stick it in the carb throats and listen through it while adjusting the carbs until the "hiss" sounds the same.  

New Driver

You can also remove the probe from the stethoscope, and use a hose connected to the ear pieces to listen around your noisy components. Works a lot better than the hose by itself. 

Pit Crew

My first day on this site. very nice, informative thank you.

Passenger

didn't punch da "show more" button & just skimmed the article but didn't see any1 mention safety. Guys get stuff poke into them and jerked offa them doing these exams. Be careful when jumping into these 'experiments'.  Even those of us w/experience need to use caution...thnx for the write up'n pic.

Intermediate Driver

Just did a quick check. Vibrate Software. Used to be able to get a one day trial but no longer. The software is $400. A few good shops have it.

Intermediate Driver

I used to teach this stuff. NVH noise vibration and harshness. Lots of high tech stuff. Chassis ear: multiple pick ups that could be placed on various parts with a seven channel switch box to send the noises to head phones, vibration analyzer with little computer: enter pulley sizes, gear ratios, tire sizes etc. great tool! “Vibrate” software...amazing computer program. And my favorite: lawn mower tachometer. Place on a component or even a window. Tune to maximum wiggle and read the frequency or rpm. Most guys hate this stuff but I had a graduate that specialized in this stuff: 80k a year. Said he never got dirty working on cars.

Intermediate Driver

Add a small funnel, about the size of your ear, on the hearing end of the heater hose for ease of use and amplification. Press the funnel to your ear and you isolate the sound from the ambient noise.

Pit Crew

You can also use a very old school method.  Weld or braze either a welding or brazing rod to the bottom of a soup or similar size can.  It makes an excellent stethoscope

Passenger

Please send your proofreader back to grade school English class , a principal is the head of an organization a principle is a concept which guides the actions or functions of a process or device . It's really not that difficult !

Passenger

Tried all three methods. They work.

Pit Crew

Great suggestions.  I have used all of them except the hose.  I just learned another new trick.  I would also caution people to be careful when working around the front of a running engine not to catch the probe, etc in the fan belt, pulleys or fan.  That will get your attention in a hurry!

New Driver

I've used a long shaft screwdriver or a wooden dowel ever since I learned to wrench on a car, which started when I was about 6 or 7 helping my dad work on his toys and when I started working on my own, I learned to use a broom handle cut to a smaller length to diagnose any strange sounds I heard from my little 265 cubic inch '55 Chevy I had in high school. That's one car I wish I still had...LOL.

Passenger

I've used a sawed off broom stick for years. I have the mechanics stethoscope but far prefer the stick, it provides more of a specific sound for each different type of noise.  After a lifetime of repairing things you get sense of what each different tone likely is. Evan the dreaded " Oh no that's a rod bearing".   Jim

Pit Crew

Putting a funnel in the hose that your ear fits in makes it easier as well.

New Driver

My high school auto mech teacher taught me a simple old school method. A one inch by 3 foot wood dowel can be used to find where a noise is coming from. Place one end  on the suspect area and then put the other end on your upper front teeth!!!  You gotta be careful but it works like a charm! You can find a sticky valve or lifter easy......that tap will vibrate your skull when you are over the bad set!!! Plus lots of other uses for the dowel!!!  

Pit Crew

Excellent suggestions.  Just wish we had some concrete tools for understanding the noises coming from our significant other like these! 🤣

New Driver