How to Diagnose and Fix Connecting Rod Bearing Noise?
2 Answers
Connecting rod bearing noise can be diagnosed and fixed by the following methods: 1. If there is abnormal noise during idle operation, which becomes more obvious as the speed increases, and a clanking sound is heard when the oil filler cap is removed, it indicates connecting rod bearing noise. Check if the connecting rod bolts are loose; 2. Push and pull the connecting rod cap up and down by hand to check. If there is excessive play, it means the connecting rod bearing is excessively worn and should be replaced with a new one; 3. If the noise is louder near the side of the engine oil pan, the oil pressure gauge shows a drop, and after the engine cools down, metal alloy particles are found in the oil drained from the crankcase, it indicates that the alloy layer of the connecting rod bearing has peeled off. Replace the connecting rod bearing and check if the connecting rod journal is damaged.
With over a decade of experience in auto repair, I can say that connecting rod bearing knock is a common engine issue. It sounds like a sharp metallic 'clanking' noise during acceleration, primarily near the crankcase. The diagnostic method is straightforward: start the engine in neutral, gently press the accelerator to increase RPM, and listen with a stethoscope or long screwdriver pressed against the cylinder block. If the noise comes from below and metal shavings are found in the oil, you've likely identified the problem. The solution requires disassembling the lower engine section to inspect bearing wear. Replace worn bearings and thoroughly clean the oil passages – this repair can't be delayed, as crankshaft damage would lead to prohibitively expensive overhaul costs. For prevention, use premium full-synthetic oil changed every 5,000km, which avoids 90% of such failures. Remember: professional tools are essential – novices should never attempt this blindly, as engine damage outweighs any potential savings.
