What is the method to determine engine knocking?
2 Answers
Method to determine engine knocking: Listen at the engine oil filler port. If the knocking sound is obvious at idle speed, use a screwdriver to short the spark plug and test each cylinder one by one to identify which cylinder is producing the sound. Alternatively, inject a small amount of engine oil into the cylinder, install the spark plug, and start the engine. If the knocking sound weakens or disappears but reappears after a while, it can be determined that it is the knocking sound from that cylinder. If a noticeable knocking sound still occurs after the engine reaches normal operating temperature, the cause should be promptly identified and eliminated. The main causes of engine knocking are: 1. Excessive clearance between the piston and cylinder wall; 2. Poor lubrication of the cylinder wall.
I remember the first time I encountered engine knocking, the sound was like a little hammer tapping inside the engine, especially noticeable during cold starts in the morning. You can park in a quiet garage or by the roadside, turn off the AC and music, and carefully listen to the engine idling. If you hear rhythmic metallic knocking sounds like "dong dong" or "kuang kuang," it's most likely engine knocking. Checking the oil level and color is also crucial; if the oil is too low or has turned black and thin, insufficient lubrication can cause the piston to loosen and collide with the cylinder wall. I didn't address it in time back then and ended up spending thousands on an engine overhaul—I still regret it when I think about it. So, once you've identified the issue, don't hesitate. Quickly take it to a professional auto repair shop to confirm the root cause using a stethoscope or compression test. Addressing it early can save you from bigger problems and save you both money and hassle.
