How to Diagnose Abnormal Engine Noises?
2 Answers
There are two methods for diagnosing abnormal engine noises, namely the manual experience auscultation method and the instrument-assisted diagnosis method. The following is a detailed introduction to diagnosing abnormal engine noises: 1. Manual experience auscultation method: Technicians reproduce the abnormal noise by changing engine operating conditions and other measures, identify the characteristics and patterns of the noise, and understand the engine's operating status and fault symptoms when the noise occurs, thereby determining the location of the noise. This is currently the most common and primary method used. During the process of diagnosing engine abnormal noises, a screwdriver is often used to listen to the noise. 2. Instrument-assisted diagnosis method: Due to the lower accuracy of the manual experience auscultation method, some instruments and equipment are commonly used to assist in auscultation and analysis. Commonly used instruments mainly include stethoscopes, noise meters, vibration analyzers, etc.
I've also experienced engine noises before, and this issue really requires careful consideration. Don't panic at first—listen carefully to the characteristics of the noise, whether it's a clattering sound or a humming noise. It's usually most noticeable during cold starts. Like the last time my car's belt was loose, there was a whistling sound at idle. Try varying the RPM to see if the noise changes, and rev the engine while stationary to check if the noise frequency speeds up. Perform a simple inspection of the belt tension and look for any cracks or signs of aging. Also, check the engine oil level—low oil can cause insufficient lubrication, leading to metal friction sounds. Loose underbody panels are also a common but easily overlooked issue. However, engine noises can stem from many causes, such as timing chains, water pumps, or bearings acting up. I remember last time the repair shop used a stethoscope to pinpoint a connecting rod bearing issue. If you can't figure it out yourself, don't force it—take it to a professional mechanic to scan for trouble codes. After all, engine repairs aren't cheap.
