Engine Knocking Repair

What knocking is

Knocking, also called pinging, most often happens when the air-fuel mixture is wrong and the fuel burns in uneven pockets instead of smooth bursts. Run with a knock too long and it can damage pistons and cylinder walls.

A higher-pitched ticking can be a different issue: loose valves and lifters, or not enough oil reaching the upper cylinder head.

Common causes

• Fuel with a lower octane rating than the engine was designed for
• Carbon buildup on valves, spark plugs, and internal parts
• Incorrect or wrongly gapped spark plugs
• Incorrect ignition timing
• A lean air-fuel mixture
• Overheating
• A failed knock sensor

What helps

Use the octane level your manufacturer recommends. An octane booster can help if low-octane fuel gets in by mistake. A technician can check for and remove carbon buildup, and correct spark plugs address the spark plug cause.

When to stop driving

Fuel and spark causes are often straightforward to correct, but knocking that continues can cause serious damage.

A deep, heavy knock that gets louder with RPM, or a knock with the oil light on, can mean worn bearings. Stop driving and have it towed in.

For lighter pinging or ticking, bring the car to us soon. Our ASE-certified technicians will find the cause.