Rod Knock (Big-end Knock)
Rod knock is a deep, rhythmic knocking from inside the engine caused by a worn connecting rod bearing.
What is Rod Knock (Big-end Knock)?
It usually gets louder with engine speed and load. Low oil pressure or oil starvation is a common cause. It often appears with an oil pressure warning. The noise often changes or fades briefly when the spark to the affected cylinder is cut, which helps locate the cylinder. Oil analysis can show bearing metal.
How it works
Extra clearance in the big-end bearing lets the connecting rod hit the crankshaft on each stroke.
Why it matters for your car
Stop driving: a failing bearing can break the connecting rod and destroy the engine. Repair usually means an engine rebuild or replacement.
Other terms
- Battery Passport (EU)
- Boost Leak
- Clutch Kit
- Coil-on-plug Ignition
- Crank But No Start
- CVT (Continuously Variable Transmission)
- EU Tyre Label
- Exhaust Flex Pipe
- Fuel Pump Relay
- Impact Wrench (Impact Gun)
- Keyless Start (Push-button Start)
- Main Beam (High Beam, Full Beam)
- Microfibre Towel
- Rain Sensor
- Seatbelt Load Limiter
- Smart Repair (Small Area Repair)
- Thermistor (Temperature Sensor)
- Tyre Blowout
- Tyre Noise (Rolling Noise)
- Wasted Spark Ignition