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.
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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.
Absolute mechanical knowhow!! But the government will probably spend $15,000 on each screwdriver to do the checking. So much for savings. Onward through the clatter!!
I was pretty fresh out of vocational school for auto mechanics back in '78 when I started working on co-workers cars. This one car had a weird sound that I couldn't determine what it was. I went to an old-school mechanic friend of mine. He took a length of heater hose and put one end to his ear and started listening around the engine for the source. Within a very short period of time he determined that the spacer block between the intake manifold and the carburetor had a leak in it. Sure enough. I went into town, bought a new one, slapped in on and it solved the problem. I was so impressed that he diagnosed it so quickly with such a "crude" tool. To be "book smart" is one thing but to have real-world knowledge is even better!
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.
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!!!
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
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.
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.
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!
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 !
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.
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.
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.
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