Thinking about buying a used Mazda Demio (2002–2023) in New Zealand? We've documented 18 known faults for this model spanning body & rust, engine, brakes, and transmission. Each researched and verified before it's published. The most serious issues here are rated critical. Two are set out in full below — the rest, with the symptoms, repair costs and checks for each, are free with an account.
18
Documented faults
Critical
Most serious
$280–$850
Typical repair
6
Systems covered
Known Mazda Demio faults
Every fault below is documented specifically for this model — researched and verified before it’s published.
01DE Rear Sill and Rear Wheel Arch Rust Perforation
CriticalCommonBody & Rust $600–$3,500 to fix
The DE-generation Demio (2007–2014) has a documented weakness in the steel panel thickness and factory anti-corrosion treatment at the rear sills (rocker panels below the rear doors) and at the inner lip of the rear wheel arches. Road stone chips break the paint at the arch lip, and road grime and moisture accumulate in the box section of the rear sill through poorly draining drain holes. Rust progresses from inside the panel outward, perforating the outer skin and, in advanced cases, compromising the structural sill section that carries the rear seat belt anchor and body stiffness.
Symptoms to notice
Visible rust bubbling, blistering paint, or orange staining along the lower rear sill panel below the rear door
Perforated or soft metal at the rear wheel arch lip, often first visible as a ragged rust edge at the top of the arch
Moisture or rust staining visible on the interior floor carpet adjacent to the rear sill when the carpet is lifted
What to check
Inspect the rear sill from the rear wheel arch forward — poke the lower sill with a blunt instrument; perforation or softness indicates active rust. Inspect the rear wheel arch lip all the way around with a torch, looking for bubbling paint, rust bloom, or perforation starting at the arch edge. Check the inner arch liner behind the wheel for trapped mud concealing rust. If a workshop inspection is possible: Lift the rear carpet and check the floor above the sill box section for moisture or rust staining.
Where to look: Rear sills (rocker panels) below the rear doors, and inner lip of rear wheel arches both sides
Ask the seller
“Has any rust repair or panel work been done to the rear sills or wheel arches?”
“Have you inspected under the rear carpet for moisture or rust staining?”
A documented pattern across the Mazda2 DJ and contemporary Mazda models (CX-3, Mazda3 BN) involves refrigerant loss through micro-pitting on the aluminium evaporator core. The cause is traced to formicary corrosion initiated by formic acid from organic material in cabin air reacting with the aluminium fins in the presence of moisture. The system loses cooling capacity gradually over one to two seasons before the compressor begins cycling abnormally. Evaporator replacement requires dashboard disassembly, making it a labour-intensive repair.
Symptoms to notice
Gradual loss of air conditioning cooling performance over one or two summers
Compressor clutch cycling rapidly on and off rather than holding engagement
Musty smell from vents as evaporator surface stays damp without proper refrigerant flow
Low refrigerant confirmed on gauge set despite no visible external leak
What to check
Operate the air conditioning on maximum cool and check vent outlet temperature with a thermometer — should reach 5–8°C on a mild day. Listen for the compressor clutch cycling on and off rapidly (short-cycling indicates low refrigerant charge). Have a refrigerant dye or electronic leak test performed if cooling is marginal.
Where to look: HVAC box behind dashboard — evaporator core (centre of dashboard, passenger side)
Ask the seller
“Has the air conditioning ever needed a re-gas, and if so how many times?”
“Does the A/C still cool to a cold temperature on a warm day, or has it become marginal?”
“Has any workshop performed a refrigerant dye or electronic leak test on the system?”
EngineCritical
BrakesCritical
EngineMajor
TransmissionMajor
TransmissionMajor
EngineMajor
TransmissionMajor
SuspensionMajor
BrakesMajor
SuspensionMajor
BrakesMajor
EngineMajor
ElectricalMajor
EngineMinor
Body & RustMinor
EngineMinor
16 more documented faults on the Mazda Demio
Symptoms, what to check, where to look and what to ask the seller — for every fault above. Free with an account, no card needed. One account covers one vehicle, so make it the car you’re actually looking at.
This page covers the model. Enter the plate of the actual car you’re looking at and see its year, engine, safety rating and register flags — free, no account needed.
Like any used car, it depends on the specific example and its service history. Across the 18 documented faults for the Mazda Demio, the recurring problem areas are body & rust, engine, and brakes. A Mazda Demio with a full service history and no signs of the issues listed on this page can be a sound buy but each one needs to be checked individually before you commit.
What are the most common problems with a used Mazda Demio?
+
We've catalogued 18 known faults for the Mazda Demio, covering body & rust, engine, and brakes. Two are written out in full on this page. The rest — with the symptoms to notice, what to inspect, and typical repair costs for each — are free once you create an account.
How much do repairs cost on a Mazda Demio?
+
Most single repairs on the Mazda Demio fall between $280–$850 at NZ independent-workshop rates. Some of the 18 documented faults cost less and a few cost considerably more, and no one car needs them all. Knowing which ones to look for before you view is what lets you negotiate the price down or walk away.
Should I get a pre-purchase inspection on a Mazda Demio?
+
Yes. A Mazda Demio inspection focused on its known weak points is the single best way to avoid an expensive mistake. KickTyres gives you a guided, model-specific inspection plus a market valuation and negotiation figure for $17.90 far less than the cost of missing one of the faults on this page.