6 Engine Noises That Require Immediate Attention

by Lori Straus

Owning a car means you own a very complex piece of machinery that seems to come with its own language when it’s in trouble. Do you hear regular knocking under the hood? Or squealing? Or perhaps more of a grinding? And what do these sounds mean? In this blog post, we’ll cover six engine noises that tell you to visit your mechanic ASAP.

Grinding or Rubbing

A rubbing or grinding engine noise could be a cry for more oil. Newer cars may have a sensor that tells you via a light on your dashboard your oil is too low. Older cars will rely on your regular inspection. But if you hear that noise coming from your engine, check your oil levels regardless of the age of your car.

A grinding sound when your vehicle is in gear can mean your automatic transmission has a failing torque converter. Low levels of transmission fluid and damage to the needle bearings can cause this problem. Have your mechanic take a look.

Check Engine Light + Sputter/Rumble

If your check engine light has lit up, and you hear a sputter or rumble coming from the engine, your car could be leaking exhaust. This is also a reason to high-tail it to your mechanic: exhaust is hot enough to melt plastic and also contains carbon monoxide that can leak into the cabin. It can also cause a loss of power and/or mileage. Regardless of the potential outcome, this car engine issue requires immediate attention.

Knock, Knock. Who’s There?


Bearings who?

Bearings in your engine might be wearing out, which means your engine might seize. A seized engine = engine failure and a very expensive car repair bill.

However, if you hear a metallic knock while you’re driving, you’re probably hearing a detonation knock. This happens when the fuel and air mixture in the cylinders detonate in more than one place at the same time. Reasons for this range from cheap (wrong kind of gas) to expensive (engine repair). But have it looked at immediately.

Lots of Noise

A muffler is called a muffler for a reason. So, if your car in general sounds really loud, take it to the garage. Technically , a muffler isn’t part of the engine, but a faulty one can lead to carbon monoxide leaks in the cabin, which can cause death. So we’re including a faulty muffler in our list of engine noises because the noise can sound like a loud engine.


If you hear a loud bang that sounds like a firecracker, pull over and get your vehicle towed to a garage. You likely just heard a backfire, which happens when unburned fuel leaks out of the combustion chamber and combusts in the exhaust. A backfire can quickly damage your vehicle.


Squealing under the hood can signal a few problems. If you hear squealing only when turning, then the steering system likely needs an inspection. If you hear it only when you brake, your brake pads may have worn down too far and need replacement. However, if you hear squealing often, the culprit could be your serpentine belt. This component controls vital engine parts such as the water pump and alternator. Whatever the cause of the squeal, get it checked out.

Engine Noises Are Usually Serious

As you likely gathered by reading our list, any noise coming from your engine should send you to your mechanic right away, even if it’s inconvenient. Cars are extremely complex, and once one component breaks down, it can cascade through your vehicle. So don’t delay: get your engine inspected immediately if you hear something.