An unlikely car repair tool for the do-it-yourselfer is a stick or piece of wood much like a yardstick. It won't help you fix much of anything, but it can help you pinpoint the source of abnormal noise in your car engine.
Here is how it works. Any abnormal noise is a type of vibration. An object like a rigid stick will transmit vibration over its length, so you can use it as a sort of stethoscope to identify sources of trouble in your engine compartment. It's not especially comfortable to use, but it works.
To use this homemade stethoscope, simply place one end of the stick on suspected sources of vibration (while the engine is running) and place the other end up against your ear. Gently press closed your ear opening with a blunt end of the stick and your closed ear will act much like a speaker, allowing the sounds to be transmitted to your ear drum so you can determine the location and nature of the noise.
By placing the stick against your closed ear, you block out distracting noises of the engine and focus only on noises that produce vibration in proximity of the stick. You'll be amazed at how clearly you can hear things like bearings, push rods, valve lifters and rocker arms - anything that is moving, clicking, rubbing or slapping up against something else.
Using this technique for diagnosing the nature of car repair through sounds helps you pinpoint the source of trouble and obviates removal and internal visual inspection to diagnose the nature of the problem.
A word of caution: be very careful while placing the stick against engine components as it can be harmful to you if it gets caught up in the fan blades, fan belts or other moving parts of the engine.
The best approach is to put the stick in place first and then position it on the outside of your ear. This allows you to see where you're placing the stick so you can avoid moving parts.
