Mechanics Stethoscope

Mechanics Stethoscope: Looks and functions like the stethoscope a doctor uses to listen to heart and lungs. Has a long thin metal probe on the end.
These are very useful for finding the souce of noises like bad pully bearings, engine noises etc.
They can be gotten at many parts stores in the $7-10 range. Harbor Freight has them for around $5.99 (2005) and sometime has them as low as $2.99. Harbor Freight PN is # 41966-6CDB

Another option:

http://www.sonictechnology.com/audiotech_probe.htm

I am familiar with the item and it works.

Google audiotech probe, shop around maybe save a buck or two