Exhausts and mufflers repaired properly, emission faults fixed at the cause.
From a rattling heat shield to a blocked DPF, we find the fault, show you the evidence and quote before we touch it. Exhaust and emission diagnosis is done within the hour at our East Tamaki workshop.
What an exhaust actually does
Your exhaust has three jobs. It carries combustion gases from the engine to the back of the car so fumes stay away from the people inside. It keeps engine noise to a level that is comfortable inside and legal outside. And, because every system is designed with the right pipe diameters and muffler volumes, it maintains the back pressure the engine was tuned for, which is what gives you full power at the lowest fuel use.
Modern systems also carry the emission hardware: the catalytic converter, and on diesels the particulate filter (DPF), EGR circuit, NOx sensors and AdBlue injection. When any of those misbehave the dash lights up, and that is where most of our exhaust work now starts.
The parts, front to back
- Front pipe or extractor, bolted to the manifold or turbo
- Flexi joint, which absorbs engine movement and is a common leak point
- Catalytic converter, and on diesels the DPF
- Intermediate pipes and resonator
- Main muffler
- Tail pipe or rear muffler
Each section can be replaced on its own, so a failed muffler does not mean a whole new system.
Why exhausts fail
Rust from the inside out. Exhaust gas contains water and sulphuric acid. If the system never gets hot enough to dry out, that mix sits in the pipes and the muffler baffles and corrodes them from within. The first sign is usually pinholes or a crack near a seam.
Short trips. A car used for school runs and supermarket trips corrodes its exhaust much faster than one that does regular motorway drives, simply because the muffler never dries out. The same driving pattern is also the main reason diesel particulate filters block.
Life underneath the car. Stones, water, speed humps and the occasional kerb all hit the exhaust first. Hangers stretch, heat shields rattle loose and flexi joints split.
Warning signs worth acting on
- The car sounds louder than it used to
- Fuel use has crept up or the engine feels flat
- Rust is visible on the pipes or muffler
- A rattle or knock from underneath, especially at idle
- Holes, cracks or sooty marks where gases are escaping
The one sign that is urgent
If you can smell fuel or exhaust fumes inside the car, even faintly, book it in straight away. A leak upstream of the cabin floor can let carbon monoxide in, and you will not notice it until it affects you. We will fit you in the same day for this.
Emission device faults
Autoworld specialises in the emission systems other workshops send away. A DPF, EGR, AdBlue or NOx fault is diagnosed within the hour using dealer-level equipment, and in most cases the fix is a forced regeneration, a cleaned filter, a sensor or a software update rather than an expensive replacement part. If a replacement really is needed, we tell you why and show you the data.
Booking
Book an exhaust or emissions inspection online, or call 022 3900 587 and describe the noise or the warning light. We will diagnose it within the hour, phone you with a plain-English explanation and a quote, and only proceed once you have said yes.
Common questions
How do I know my exhaust needs attention?
The usual signs are a louder note than normal, a rattle or knock from underneath, visible rust on the pipes or muffler, and a drop in power or fuel economy. Any smell of fumes inside the cabin is a reason to stop driving and call us, because carbon monoxide can build up without warning.
Do you replace the whole system or just the failed part?
Only what has failed. Exhausts are built in sections, so a rusted muffler or a cracked flexi joint can be replaced on its own. We show you the failed section and quote the repair before any work starts.
My DPF or AdBlue warning is on. Is that an exhaust job?
Yes, and it is one we see every week. Emission devices live in the exhaust, and most faults are caused by short trips, a sensor or a software issue rather than a dead filter. We diagnose within the hour and fix the cause rather than resetting the light.
Can you fit a performance or stainless exhaust?
We can supply and fit stainless and performance systems for most popular makes, and we make sure the result still meets WOF noise limits.
Why does my exhaust rust from the inside?
Combustion gases carry water and sulphuric acid. On short trips the muffler never gets hot enough to dry out, so the mix sits inside the pipes and eats through from the inside. Cars that do longer runs tend to get a far longer life from the same system.
Enquire or book: Exhaust systems
Tell us about the car and what it needs. We reply within the hour during workshop hours and confirm every booking by text or email.
Thanks, your enquiry is on its way.
We will confirm your booking by text or email, usually within the hour during workshop hours.