What are the solutions for engine knocking?

[KaiMarie]

Engine knocking can be addressed by: 1. Delaying the ignition timing; 2. Cleaning the fuel system and injectors; 3. Using qualified fuel additives; 4. Choosing fuel suitable for the engine's compression ratio; 5. Repairing or replacing the water pump. The causes of engine knocking include: 1. Carbon deposits in the combustion chamber; 2. Low fuel octane rating; 3. Incorrect ignition timing; 4. Overheating of the engine; 5. Incorrect air-fuel ratio. Engine maintenance methods include: 1. Using high-quality engine oil; 2. Using qualified coolant; 3. Regularly cleaning radiator scale; 4. Periodically removing carbon deposits from the car; 5. Timely replacement of the car's air filter, oil filter, and fuel filter.

[OAxel]

I've experienced this before. Last time when I was driving my old car on the highway, I also heard loud knocking sounds from the engine bay, which was quite scary. The repair shop later told me it was engine knocking, mainly caused by using low-quality gasoline. The mechanic advised me to immediately release the throttle to reduce RPM when knocking occurs, and not to press hard. Afterwards, it's best to switch to a reputable gas station and use higher-octane fuel, as long-term use of low-octane fuel can cause problems. Also, spark plugs should be replaced when needed - aged plugs with inaccurate ignition timing can also lead to knocking. For cars with severe carbon buildup, the combustion chamber needs cleaning. I personally use fuel additives regularly with decent results, but serious cases require disassembly cleaning. Knocking damages the engine, so address any abnormal sounds promptly.

[LeDonovan]

From a mechanic's perspective, the first things to check for engine knocking are the fuel and ignition systems. The most common issue is using gasoline with an incorrect octane rating, so it's recommended to switch to qualified fuel with the manufacturer-recommended octane rating. Aging ignition coils causing abnormal ignition timing is another frequent cause, requiring spark plug and coil replacement when necessary. Carbon buildup in the combustion chamber alters the compression ratio and can lead to spontaneous ignition of the end-gas mixture, necessitating carbon cleaner application or mechanical cleaning. If the knock sensor fails, it can't detect knocking signals, preventing the ECU from adjusting ignition timing - this requires immediate replacement. Abnormal cylinder pressure or cooling system malfunctions may also induce knocking, suggesting comprehensive diagnostic testing is advisable.

[SanCarson]

Don't panic when knocking occurs, avoid stomping the accelerator. Last time I heard metallic knocking sounds on the highway, I immediately switched to manual mode and downshifted to lower the RPM. The most practical solution is trying a tank of higher octane fuel - if 95# doesn't work, try 98#. For older vehicles, remember to use fuel system cleaner to remove carbon deposits, and replace spark plugs if they've exceeded 30,000 km. Overheating can also cause knocking, so check your coolant level. If the noise persists, head straight to a repair shop for OBD diagnostics - they can test the knock sensor's operation and professionally adjust ignition timing.