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.
Engine knocking, or pinging, is a term often used to describe an irregular sound made by a vehicle engine when there is a problem with the handling of air/fuel mixture within the cylinders.Normally, this sound is heard when the vehicle is idling and it can be either weak or strong.ollowing is a list of potential causes for an engine knocking sound: 1  Improperly mixed fuel (ie: water in the gas). 2  Timing off. 3  Irregular cylinder pressure. 4  Sharp edges on pistons or valves (due to wear and tear). 5  Low coolant level. 6  Cooling system problems. 7  Overheating. 8  Improper spark plugs.