What Causes Engine Piston Slap Noise?
2 Answers
The reasons for engine piston slap noise are: 1. Excessive clearance between piston and cylinder; 2. Incorrect piston installation direction or piston deformation; 3. Bent or twisted connecting rod; 4. Excessive carbon deposits in combustion chamber increasing diesel engine compression ratio; 5. Clogged lubricating oil passages; 6. Overly rapid combustion of air-fuel mixture. The solutions for engine piston slap noise are: 1. When engine temperature is normal but knocking sound exists, avoid high-speed operation and perform disassembly and repair as soon as possible; 2. Check whether the cylinder is severely out-of-round or scratched, and whether the piston-to-cylinder clearance is too large - replace cylinder liner, piston, and piston rings promptly if needed.
As a seasoned driver with over 30 years of experience, I can tell you that engine knocking is no trivial matter. It's usually caused by either premature ignition timing or excessive carbon buildup, which leads to uneven combustion and produces that distinct tapping sound. Don't underestimate it – prolonged knocking can wear out piston rings or cylinder walls, and in severe cases, even cause engine seizure. My old Toyota once had this issue, and it nearly led to disaster. My advice? Shut off the engine immediately and have a professional technician inspect the spark plugs, sensors, and fuel system. Never attempt DIY fixes on this. Also, incorrect air-fuel ratio or using low-quality gasoline can also trigger knocking, so regular maintenance and using good fuel are crucial. Remember, safety comes first – don't wait until the noise gets worse to regret inaction.
