Common Engine Noises and When to Call an Auto Repair Shop
When Should You Take Your Car to an Auto Repair Shop for Engine Noises?
If you're wondering, "When should I call a mechanic about engine noises?", the safest answer is anytime the noise is new, persistent, getting louder, or accompanied by performance problems such as warning lights, overheating, loss of power, or rough running. Even small, strange sounds can indicate early stages of major problems. Addressing them quickly often saves hundreds—or even thousands—on future repairs.
Key warning signs that require immediate attention:
- Knocking or pinging (detonation)
- Grinding or metal-on-metal sounds
- Loud banging or backfiring
- Persistent hissing or steam under the hood
- Clattering or rattling that doesn’t go away at normal temperature
Common Engine & Vehicle Noises
1. Squealing or Screeching
A squealing or screeching noise coming from your engine, is most often caused by a loose or worn serpentine belt that drives essential systems like the alternator, power steering, and A/C. When the belt slips, it produces a high-pitched squeal that may get louder during acceleration or when turning on accessories. Left unchecked, a failing belt can snap—leaving you stranded and disabling multiple systems at once.
Possible solutions:
- Inspect for cracks or fraying in the belt
- Adjust belt tension or replace as needed
- Check condition of pulleys and tensioner
2. Tapping, Clicking, or Ticking Sounds
If you are hearing a tapping, clicking or ticking sound, it usually points to low oil pressure or low oil level. This causes poor lubrication of moving parts like lifters and valves, leading to metal-on-metal noise. Persistent ticking could also mean worn lifters, valve train wear, or a failing camshaft component—problems that worsen quickly if not addressed.
Possible solutions:
- Check and top off oil level
- Change oil and filter if overdue
- Have valve train components inspected if noise persists
3. Grinding Noises
If you hear grinding from your engine, this is one of the most serious warning signs—indicating metal components are scraping together without enough lubrication. Common causes include worn main or rod bearings, a failing starter motor engaging incorrectly, or severe internal engine damage. Continuing to drive with grinding noises can result in total engine failure.
Possible solutions:
- Stop driving immediately if grinding persists
- Check oil level and condition
- Have a mechanic inspect for internal wear or starter motor issues
4. Knocking or Pinging (Detonation)
If you’re hearing knocking or pinging, your engine is experiencing abnormal combustion—fuel is igniting at the wrong time or unevenly. This can be caused by low-octane fuel, excessive carbon buildup, faulty spark timing, or malfunctioning sensors. Prolonged detonation can severely damage pistons and cylinder walls.
Possible solutions:
- Switch to the correct or higher-octane fuel
- Consider a professional fuel system cleaning
- Have ignition timing and sensors checked
5. Hissing or Popping Sounds
If you hear a hissing sound, especially after shutting off the engine, it may be coolant or oil leaking onto hot surfaces—or a vacuum leak allowing air to escape. Popping sounds from the exhaust may signal unburned fuel igniting in the system. Both can lead to overheating, poor performance, and emissions problems.
Possible solutions:
- Look for visible leaks or steam
- Replace worn hoses or gaskets
- Repair vacuum leaks promptly to prevent further issues
6. Rattling, Clunking, or Banging
If you're wondering, “Why is my engine rattling or clunking?”, the cause could be as minor as a loose heat shield or as major as a failing timing chain. Rattles that happen only at cold start can sometimes be piston slap, while constant, loud rattling may mean internal wear or broken components. Ignoring these noises can lead to catastrophic failure.
Possible solutions:
- Check exhaust system brackets and heat shields
- Inspect suspension and mounts for looseness
- Have the timing chain and tensioners inspected
How to Safely Diagnose Engine Noises
The best approach is to do basic, non-invasive checks and avoid actions that could worsen the damage. Identify when the noise occurs—only at idle, during acceleration, at high speeds, or continuously. Then check oil and coolant levels, look for visible leaks or damaged belts, and listen for changes as the engine warms up. If the noise is loud or worsening, stop driving and call a professional. Recording the sound on your phone can also help a mechanic diagnose the issue faster.
Safe diagnostic steps:
- Listen closely – Determine if it happens at idle, acceleration, or cruising
- Check basic maintenance items – Oil level, coolant, belts, and hoses
- Look for visible damage – Leaks, frayed belts, loose parts
- Record audio/video – Helps mechanics troubleshoot remotely
- Seek help promptly – Stop driving if noise is severe or worsening
Engine noises are your car’s built-in warning system—listening early and acting quickly is the cheapest insurance against major repairs. Whether it’s a belt squeal or a deep metallic knock, knowing what the noise means and when to call a mechanic will save money, extend your engine’s life, and keep you safe on the road.