Few things can be as unsettling when behind the wheel as a sudden noise. Noises coming from a car can indicate various issues, which is why such sounds tend to differ. Quickly identifying what’s behind car noises can make for safer driving and potentially save drivers substantial amounts of money.

Noise: Rattling coins

Problem: Loose lug nut in a hub cap

This noise can be loud and unsettling, but the good news is that it’s often a simple fix if addressed immediately. A noise that sounds like coins rattling around in a dryer is likely a loose lug nut in a hubcap. The lug nut might have become loose if a wheel was not tightened sufficiently after a recent maintenance appointment or even if drivers changed a tire on their own. The longer drivers wait to address this, the more dangerous and costly it could become, as it could have an effect on the wheel bearings. However, if handled promptly, the damage is likely minimal.

Noise: Squealing on start-up

Problem: Issue with the serpentine belt

A squealing noise at start-up is among the more annoying noises a driver can hear. This sound often indicates a worn or damaged serpentine belt, which connects the crankshaft to the alternator, power steering and additional components. Thankfully, a worn-down serpentine belt is a relatively inexpensive repair, though it must be addressed promptly. Squealing at start-up also could indicate a loose tensioner, designed to keep the serpentine belt at a certain tightness and tension, or wear and tear to the belt due to parking outside. These issues can be addressed by readjusting or replacing the tensioner or replacing the serpentine belt, particularly if the part is old.

Noise: Engine knocking

Problem: Various issues

A knocking noise from the engine typically sounds like repeated tapping. The noise will often become louder as the vehicle accelerates. Various issues can be behind the knocking sound, and drivers should avoid self-diagnosing the problem, even if they’ve experienced it in the past with the same or a different vehicle. For example, some drivers hear knocking because they’re using 87 octane fuel instead of the high-performance and more expensive fuel the owner’s manual recommends (this could be a common problem in recent months given the meteoric rise in fuel prices). Another potential cause of engine knock could be problems with the pistons or crankshaft. Regardless of what’s causing engine knocking, drivers are urged to take their vehicle to a mechanic promptly, as the cost of repairs is likely to rise the longer knocking goes untreated.

No one wants to hear noises coming from their vehicles. However, such noises should be addressed promptly, as the quickness of drivers’ responses could make the difference between a simple, less costly fix and a more time-consuming, expensive repair.