I real in a previous post about using a stethoscope, Automotive of course, to find vaccum leaks and sticking valves, and different engine problems. Q is, how well to they work and What do these individual sounds, sound like. I mean, What little things should I be listening for? Thanks anybody.

What you use is either a tube made of various materials or use a very long screwdriver.

I use a screwdriver.
With the engine running....
Place the metal end on various parts of the engine and the handle end on your ear.

I found out my bearings in my alternator were going bad by using this method.

You can also hear your lifters as well. Kinda neat to just go around the engine bay and place the screw driver on various things to "hear" how they are working on the inside.

It's not a tell all, but you can pinpoint where noises are coming from when the engine is running.

Make sure you use a long screwdriver and lots of common sense while doing this.
If you have long hair pin it back.
You'd be surprised just how fast those belts can rip a big chunk of hair out. And that's if you're lucky!!

Please be careful when doing this or anything else while the motor is running.