Definition of discourse marker noun from the Oxford Advanced Learner's Dictionary
When an engine starts knocking, one of the first things a mechanic will check is the oil pressure. A warning light may come on in the car, and adding sufficient oil will solve the problem. Sometimes, a knocking noise is caused by loose torque converter bolts or a loose flywheel.
There is a misconception in the world that high octane fuel will make your car go faster or run better. This isnot true. The octane rating only rates the fuelâs resistance to engine knocking. Knocking or pinging is a sound that an engine makes when the air-fuel mixture in the combustion chambers ignites too early.