In the descriptive sense, people speak of luck after events that they find to be fortunate or unfortunate, and maybe improbable. Therefore, cultural views of luck vary from perceiving luck as a matter of random chance to attributing to such explanations of faith or superstition.
Chirping can be due to misalignment of the drive belt, but could also be due to pulley misalignment, worn pulley bearings, worn belt ribs, contamination from oil, coolant, power steering fluid, brake cleaner, belt dressing, or other substances. Squealing is usually caused by slipping between the belt and the pulleys.
ENGINE BEARING NOISE. A deep rapping noise from the engine is usually rod knock, a condition brought on by extreme bearing wear or damage. If the rod bearings are worn or loose enough to make a dull, hammering noise, you're driving on borrowed time.n engines with hydraulic lifters, oil pressure pumps up the lifters when the engine is running to maintain zero lash in the valvetrain. This results in quiet operation. So if the rocker arms are clattering, it tells you something is amiss (bad lifter or worn or damaged parts) or the rocker arms need adjusting.