Exhaust noise: rumbling, rattling or hissing?

Does your car suddenly sound louder, does it rumble when you pull away or is something rattling underneath? Then the problem is often in the exhaust. Below you can read which noise fits which cause, what you can check yourself and when you should have the car checked soon.

By the team at Autobedrijf Willemsbrug, RDW-approved APK (MOT) test station since 1979 · Updated 6 November 2026

Our score is 4.8 / 5 from 235 reviews. Read what our customers say

The short answer

If the exhaust sounds louder or deeper than normal, especially when you accelerate, there is often a hole or leak in it. Popping or hissing while the engine is running also points to a leak. If something rattles under the car, the inside of a silencer or the catalytic converter may have come loose, or the exhaust is no longer held securely. If you smell exhaust fumes inside the car, open the windows and have the car checked soon, because exhaust gases contain carbon monoxide.

Exhaust repairs at Autobedrijf Willemsbrug: we first check whether a repair is enough. We weld, replace a single part or make a section to measure, and we replace catalytic converters and oxygen sensors after a diagnosis. We do not clean, replace or remove diesel particulate filters. We tell you the price in advance based on your registration number. Call +31 10 479 00 00. You bring the car and we call you when it is ready. A loan bike is free while one is available. Bringing the car on a Saturday is possible by arrangement. Our team speaks English. More about exhaust repairs

Which noise points to which problem?

Each type of noise fits a different problem. The overview below helps you judge what is going on. You only know for certain once the car is on the lift and someone listens and looks underneath with the engine running.

What you hear Possible cause What to do
The car sounds louder, deeper or rumbling, especially when accelerating Possible causeA hole or leak in the exhaust, for example in the rear silencer What to doHave the exhaust checked soon
Popping or hissing while the engine is running Possible causeA leak in the exhaust or at a joint What to doHave the exhaust checked soon
Rattling from a silencer Possible causeInternal tubes in a silencer that have rusted loose What to doHave the silencer checked
Rattling near the catalytic converter Possible causeThe inside of the catalytic converter has come loose What to doHave the catalytic converter and the engine checked
The exhaust hangs lower or moves a lot Possible causeCracked rubber hangers or rusted-through brackets What to doDo not drive on if the exhaust touches the road
An unpleasant smell or exhaust fumes inside the car Possible causeA leak that lets exhaust gas into the car What to doOpen the windows and have the car checked soon

Sources: ANWB, Uitlaat (exhaust) and Katalysator (catalytic converter), and Walker (Tenneco), Symptoms of an Exhaust Leak and Signs and Symptoms of a Bad Muffler. Consulted November 2026.

Is the noise not coming from the exhaust, but from the wheels, the brakes or the engine, for example? Our page car making a noise: find the cause gives an overview of other noises.

Rumbling or a louder sound: why does a leaking exhaust sound like this?

A leaking exhaust sounds louder because the exhaust gases escape before the silencers have done their job. The middle silencer and the rear silencer damp the sound. If there is a hole before or in a silencer, you hear the engine with less damping.

Walker, a manufacturer of exhaust systems, names louder engine noise as a common sign of an exhaust leak. You then hear a loud rumble, especially when accelerating. According to Walker, a loud noise from the back of the car often points to a hole in the rear silencer. You may also hear occasional popping or hissing while driving.

A leak has other effects too. According to Walker, an exhaust leak can increase fuel consumption, and the car can lose power if the leak is not repaired. A leak before the oxygen sensor can also trigger a fault message. You can read more about that in catalytic converter fault: is it the converter or the oxygen sensor.

Rattling under the car: silencer, catalytic converter or hangers?

Rattling under the car often comes from something loose in or on the exhaust. There are three places we look at first:

  • Inside a silencer: according to Walker, internal tubes in the silencer that have rusted through or come loose can bounce around and make noise.
  • Inside the catalytic converter: the ANWB names a rattling noise as a sign of a broken catalytic converter. The inside can come loose. A catalytic converter usually fails because of another problem, such as an engine that does not burn its fuel properly. That is why we then also look at the engine.
  • On the hangers: the exhaust hangs on rubbers and brackets. According to the ANWB, the rubber hangers can dry out and crack, and the brackets can rust. If they give way, the exhaust can break off. That is why we also check the rubber hangers and the clamps.

Why does an exhaust start to leak?

An exhaust usually starts to leak because of rust. According to the ANWB, an exhaust is a wear part. Rust usually starts at the rear silencer, because the gases there have partly cooled down and condensation forms. In the end the rust causes holes and the exhaust starts to leak.

It also happens from the inside. Walker writes that moisture from the heating up and cooling down of the silencer can collect inside and cause rust there. If you mainly make short trips, that moisture evaporates less well. According to the ANWB, an exhaust can then rust through after four or five years. If you drive a lot and the exhaust gets properly hot, it can last as long as 10 years.

The flexible section in the exhaust, close behind the engine, absorbs the movements of the engine. A leak can form there as well.

Can you smell exhaust fumes inside the car?

If you smell exhaust fumes inside the car, there may be a leak that lets exhaust gas in. Walker names the smell of exhaust fumes inside the car as a sign of an exhaust leak. According to Walker, fumes from a damaged silencer can get into the car, and many harmful exhaust gases have no smell. So you will not notice every leak by its smell.

Exhaust fumes inside the car? Open the windows and have the car checked soon. Exhaust gases contain carbon monoxide, and you cannot smell it. Call +31 10 479 00 00 and we will see when the car can come in.

Can you still drive with a leaking or rattling exhaust?

That depends on what you hear, smell and see. Use these rules of thumb:

  • The car sounds louder, but you smell nothing inside: you can drive to the garage, but do not wait too long. You will not notice every leak by its smell, and according to Walker a leak costs fuel and power.
  • You smell exhaust fumes inside the car: drive with the windows open and keep the trip as short as possible. Have the car checked soon.
  • The exhaust is hanging loose, touching the road or dragging: do not drive on. Call us for advice.
  • The engine warning light is on or flashing as well: have the fault codes read as soon as possible.

Welding, replacing one part or a new exhaust?

We first check whether a repair is enough. Welding, replacing a single part or making a section to measure is often possible. According to the ANWB, small holes can sometimes still be welded or sealed with a special paste. If one silencer is worn out, we only replace that part. According to the ANWB, replacing only the middle or the rear silencer takes about an hour of work.

  • Welding: a hole or crack in a part that is otherwise in good condition.
  • Rubber hangers and clamps: replaced if they are cracked or rusted through.
  • Replacing a single part: the rear silencer, the middle silencer or the flexible section.
  • Made to measure: a section of exhaust that we make ourselves, if a separate part does not fit or is not available.
  • Replacing the catalytic converter or oxygen sensor: only after a diagnosis.

We tell you one price in advance, based on your registration number, and we only carry out repairs with your approval. As an indication: according to the ANWB, a rear silencer costs € 150 to € 700 (consulted November 2026). How we work is explained on our page about exhaust repair and replacement in Rotterdam. You bring the car and we call you when it is ready. Bringing the car on a Saturday is possible by arrangement.

Does a leaking or loud exhaust fail the APK (MOT)?

Yes. A leak or too much noise is a reason to fail the APK, the compulsory Dutch vehicle inspection. According to article 5.2.11 of the APK manual of the RDW (the Dutch vehicle authority), the exhaust must be gas-tight along its full length, apart from the drain holes, and must be securely fitted. The inspector looks and listens with the engine running, with the car on a lift or over an inspection pit.

  • Uitlaatsysteem niet gasdicht (exhaust system not gas-tight): the exhaust is leaking.
  • Uitlaatsysteem ondeugdelijk bevestigd (exhaust system not securely fitted): the exhaust is loose or not hanging properly.
  • Geluidsniveau hoger dan toegestaan (noise level higher than allowed): the noise is more than the value in the vehicle register plus 2 dB(A). If there is no value in the register, a limit of 95 dB(A) applies.

Rust on the exhaust is not a rejection point in itself. What counts is leaks, mounting and noise. What else is checked on the exhaust at the APK, such as the emissions and the diesel particulate filter, is explained in failed the APK on the exhaust.

Frequently asked questions

How long does an exhaust last?

According to the ANWB, an exhaust can last as long as 10 years if you drive a lot and it gets properly hot. With little use and many short trips, it can rust through after four or five years. Rust usually starts at the rear silencer.

Can a hole in the exhaust be welded?

Yes. According to the ANWB, small holes can sometimes still be welded or sealed with a special paste. We first check whether welding is enough. If a part has rusted too far, we replace only that part or make a section to measure.

How much does a new rear silencer cost?

According to the ANWB, a rear silencer costs € 150 to € 700, and replacing only the rear silencer takes about an hour of work (consulted November 2026). We tell you one price in advance, based on your registration number.

Does a leaking exhaust use more fuel?

Yes, it can. Walker names more frequent trips to the pump as a possible result of an exhaust leak. According to Walker, the car also loses power if the leak is not repaired.

Why does an exhaust rust from the inside?

Because of condensation. Moisture forms in the exhaust as it heats up and cools down. According to Walker, that moisture can collect inside the silencer and cause rust. On short trips, the exhaust does not get hot enough for the moisture to evaporate.

Do you also repair the exhaust on a van or motorhome?

Yes. We repair exhausts on all makes, including vans and motorhomes up to 3,500 kg. We have five heavy-duty lifts, including lifts for motorhomes and commercial vehicles.

Noisy exhaust? Have it checked

Call +31 10 479 00 00 with your registration number. We first check whether welding or replacing a single part is enough, and we tell you the cost in advance.

You will find us at Boterdiep 11 in Rotterdam-IJsselmonde, close to Stadion Feijenoord (De Kuip). We work by appointment. For a quick question or check you can walk in without an appointment.

Nederlands? Lees dit artikel in het Nederlands.