Proper engine noise diagnosis is a very important issue to address. In fact improper diagnosis can lead you on a wild goose chase.
For example, if you believe the engine noise is a wrist pin that is loose and you remove the engine and disassemble it and then find out that it was a camshaft thrust plate that came loose.
You will have performed a couple of day’s work that was not needed. Often a malfunction in the engine will reveal itself first as an unusual noise. This can happen before the problem affects the actual performance.
Some of these problems include badly worn piston rings or ring lands, loose wrist pins, worn main bearings or connecting rod bearings, and loose valve train components all produced telltale noises that are unique.
With a little practice a do it yourself auto mechanic can gain the experience to interpret engine noises and distinguish them from one another.
This can and will avoid a costly and time-consuming engine tare down that could be avoided. Always take the extra time to make a proper noise analysis before doing anyengine repair work. Also having a heads up on the noise can reduce repair costs by addressing the problem before irreversible engine damage occurs.
Diagnosis with a stethoscope
Some engine sounds can be easily heard without using a listening device, but others are impossible to hear and or pinpoint unless amplified. I still see a lot of auto mechanics performing engine noise diagnosis using the large screwdriver pushed up against the ear method.
This is okay for very loud noises, but not for small or developing noises. Especially since the procedure for using a stethoscope is simple and the tool is really inexpensive.
I own the Lisle on the left but I paid $30 on the Brand name tool truck. Use the tip of the metal probe on the mechanics stethoscope to trace the sound until it reaches its maximum intensity.
Once the precise location has been found, the sound can be better evaluated and diagnosed. A mechanic’s stethoscope will provide much clearer and accurate results.
The newest tools to hit the market are electronic listening devices. This may be overkill for the do it yourself car mechanic. But with this tool you can tune into the noise and cancel out surrounding noises. This can lead to even more accurate engine noise diagnosis.