5 Car Noises That Could Be Signs of Trouble

5 Car Noises That Could Be Signs of Trouble

Updated on June 12 2024

When starting or driving your car, do you hear unusual or strange noises from the engine bay? Remember that cars (and most vehicles) are not designed to make annoying sounds while in operation. For all you know, those worrying noises are trying to tell you something, and it is your responsibility as the driver or owner to pay attention and catch signs of trouble before they get worse.

But then again, not everyone is familiar with the signs (and sounds) of imminent failure. If you hear these five car noises from your car, it could be a sign of trouble, so better catch it early before a simple fault turns into a massive and expensive repair job.

5 Car Noises to Watch Out For: Trouble is Brewing

1. Squealing, shrieking or screeching noises

When people squeal or scream, it’s not a good thing. The same is true if you hear screeching, shrieking, or squealing noises from under the hood. The most likely culprit of those high-pitched underhood noises is a loose, broken, or failing serpentine belt or fan belt. And since the belt is responsible for turning the water pump, alternator, aircon compressor, etc., a worn-out fan belt deserves immediate attention.

However, if you hear a sharp, shrieking metallic noise from either the front or back while driving, it could mean the brake pads are wearing down. Brake pads have a “warning system” that utilizes a metal pin that scratches the discs if the brake pads are beyond the limit, hence causing that relentless metallic shriek. When this happens, bring your car to a mechanic or service garage immediately.

2. Knocking engine sounds

If you hear knocking or tapping sounds when accelerating or climbing hilly roads, the sound is known in automotive parlance as “carbon rap” or detonation knock. Depending on the source of the problem, it could mean one, two, or both: a dirty or clogged fuel intake system or using fuel with the wrong octane rating.

Keep in mind that the octane rating has nothing to do with going faster than the other guy using cheaper unleaded gas. The octane rating or RON (Research Octane Number) has more to do with combustibility than making your car go quick. If your car needs 95 RON premium fuel, filling up with 91 RON unleaded gas will cause knocking, tapping, or pinging noises when accelerating.

Other causes of knocking engine sounds are a faulty knock sensor, wrong engine timing, worn out or defective spark plugs (or using the wrong type of plugs), and a lean air/fuel mixture (caused most likely by a dirty or clogged air filter).

3. Grinding Noises

There are many parts in a modern vehicle that could cause grinding noises. If you hear it when driving or idling the engine, it could point to worn-out engine bearings. If you hear grinding sounds while moving, it could mean worn-out wheel bearings. But if your car has a manual transmission, you could be dealing with a failing clutch.

When grinding noises are present while braking, it could mean the brake pads are completely worn down. But if grinding noises are there when you turn the steering wheel, the most likely culprits are worn-out CV joints or steering linkages. No matter the case, grinding noises are bad news. Bring your car to a mechanic before the engine fails or the wheels fall off.

4. Rumbling, popping, or booming noises

Did you recently scrape the underside of your vehicle above those pesky humps? How about those steep parking grades all over Marikina, Quezon City, and the rest of the archipelago? If your answer is “Yes!” and you now hear rumbling or popping noises from the undercarriage, you are probably dealing with a hole in your muffler or exhaust system.

But then again, if severe vibration or shaking accompanies those rumbling or booming sounds, it could mean faulty spark plugs or a misfiring engine. When this happens, you know the drill: Have your vehicle checked immediately.

5. Hissing sounds

You better pray there’s not a snake inside your car because hissing sounds can point to an overheating engine, a leaking EVAP system, leaking hoses spilling fluids on hot engine parts, or a failing catalytic converter.

If the hissing sound is loud enough to cause worry and suddenly happens while driving, pull over and check the temperature gauge. If the engine is overheating, open the hood and check the coolant reservoir – DO NOT touch or open the radiator cap! – and add coolant or distilled water if necessary.

Hissing sounds from under the hood demand immediate attention. Bring your car to a mechanic to diagnose the problem.


When driving, it’s essential to pay attention to the road. However, a good driver also pays attention to unwanted noises coming from the vehicle. Take your car to a mechanic before a strange noise turns into a huge nightmare.