Full text: What engine noises should you never ignore?

At Mario Garage in Cagnes-sur-Mer, we often hear the same question from BMW, Mercedes, and Audi owners: “I hear a strange noise coming from the engine — what could it be?” At first, the noise might seem harmless, but it often signals a serious issue.

We always tell our clients: an engine never makes unusual noises for no reason. The sooner you identify the cause, the easier and less expensive the repair will be.

What you need to know first

A modern car engine is a complex system, and any unusual noise is a sign that something isn’t working properly.
A hum, knock, or whistle can indicate significant wear. Only a proper diagnostic can pinpoint the exact source of the noise.

Which noises are especially dangerous?

Based on our experience, especially with German vehicles, here are the top 5 engine noises you should never ignore:

• Metallic knocking sound at startup
  Could indicate issues with hydraulic lifters or pistons.

• Whistling or squealing while accelerating
  Often caused by a worn timing belt or tensioner pulleys.

• Popping sounds from the exhaust
  May point to ignition problems or incorrect fuel supply.

• Humming noise that gets louder with RPMs
  Can signal worn bearings or gearbox issues.

• Vibrations or rattling at idle
  Might be due to faulty engine mounts or air intake problems.

Even if the noise comes and goes, don’t delay a visit to the garage. It could lead to a major breakdown.

Why choose us?

At Mario Garage, we use professional diagnostic equipment designed for premium brands like BMW, Mercedes, Audi, and Volkswagen.
We don’t just locate the noise — we analyse the entire engine to eliminate the root cause and prevent further damage.

Can you keep driving with engine noises?

Sometimes — yes, but it’s risky. We’ve seen many cases where drivers kept going and ended up needing expensive repairs: broken timing chains, damaged pistons, or even complete engine rebuilds.

When should you book a diagnostic?

• If the noise is getting louder over time

• If you hear metallic knocking or grinding sounds

• If the engine runs unevenly

• If fuel consumption has increased

Come to Mario Garage in Cagnes-sur-Mer — we’ll perform a complete diagnostic and eliminate the source of the noise so your engine runs smoothly and reliably again.