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.
What Causes Engine Knocking Posted on Autos.com Editor. in Car Maintenance. on October 7, 2013. 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.