Thinking about buying a used Mazda RX-8 (2003–2012) in New Zealand? We've documented 23 known faults for this model spanning engine, cooling, suspension, and fluid leaks. 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.
23
Documented faults
Critical
Most serious
$500–$1,500
Typical repair
6
Systems covered
Known Mazda RX-8 faults
Every fault below is documented specifically for this model — researched and verified before it’s published.
01Apex Seal Failure from Carbon Buildup and Short-Trip Use
CriticalVery commonEngine $5,000–$16,000 to fix
The Renesis 13B-MSP rotary engine's apex seals are the single most documented failure point across all RX-8 production years. Carbon deposits accumulate on the rotor housing and apex seal grooves from short-trip driving, incomplete warm-up cycles, or oil injection system neglect. Seals lose their ability to maintain compression, resulting in engine that fails to start hot, produces white/blue smoke, and eventually cannot run. This failure pattern is so prevalent it defines the RX-8's reputation and must be tested at purchase.
Symptoms to notice
Engine cranks but will not start when hot (hot-start failure)
Low or uneven compression readings below 620 kPa per rotor
White or blue smoke from exhaust under hard acceleration
Rough idle or misfiring at idle
Gradual loss of power and throttle response
What to check
Start the engine cold and warm it fully to operating temperature, then shut it off. Attempt hot restart after 20 minutes — a worn engine often refuses to restart hot. Check that oil injection system is functioning. Confirm full warm-up is achieved on every drive. If a workshop inspection is possible: Perform a cold compression test — each rotor should read above 620 kPa (ideally 700–850 kPa) and the two rotors should be within 100 kPa of each other.
Where to look: Rotary engine, apex seals on front and rear rotors
Ask the seller
“Does the car always start reliably when hot as well as cold?”
“Has a compression test been done and what were the readings?”
“Was the car used mainly for short trips or regular highway driving?”
“Has the engine ever been rebuilt or replaced?”
02Engine Flooding — Cold Start No-Start
MajorVery commonEngine $80–$350 to fix
The 13B-MSP Renesis is highly susceptible to fuel flooding when started cold and shut down before reaching full operating temperature. Unburned fuel saturates the spark plugs (the engine uses two plugs per face, four total), preventing ignition on the next start attempt. Unlike piston engines, the rotary cannot expel flooded fuel through normal cranking without risk of hydrolocking or catalytic converter damage. Mazda issued a Technical Service Bulletin addressing the cold-start procedure and the minimum warm-up requirement. This is an inherent design characteristic of the engine that is exacerbated by poor ownership habits.
Symptoms to notice
Engine cranks strongly but refuses to start, especially after a recent short trip
Fuel smell from exhaust during cranking
Engine starts briefly then immediately stalls when cold
Spark plugs fouled with fuel or carbon deposits
What to check
Ask specifically about no-start history. Inspect all four spark plugs for fouling — heavy carbon or wet fuel deposits confirm repeated flooding. Verify the de-flood procedure works (hold throttle fully open while cranking for 10+ seconds). Check plug replacement history.
Where to look: Engine — spark plugs, intake tract
Ask the seller
“Has the car ever failed to start after a short trip, and how was it resolved?”
“Are you aware of the minimum warm-up requirement for this engine before shutting off?”
“When were the spark plugs last replaced?”
EngineCritical
EngineCritical
EngineCritical
CoolingCritical
CoolingCritical
SuspensionCritical
EngineCritical
Fluid LeaksMajor
EngineMajor
TransmissionMajor
SuspensionMajor
ElectricalMajor
EngineMajor
EngineMajor
Fluid LeaksMajor
EngineMajor
ElectricalMajor
ElectricalMajor
ElectricalMajor
EngineMajor
EngineMajor
21 more documented faults on the Mazda RX-8
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 23 documented faults for the Mazda RX-8, the recurring problem areas are engine, cooling, and suspension. A Mazda RX-8 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 RX-8?
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We've catalogued 23 known faults for the Mazda RX-8, covering engine, cooling, and suspension. 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 RX-8?
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Most single repairs on the Mazda RX-8 fall between $500–$1,500 at NZ independent-workshop rates. Some of the 23 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 RX-8?
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Yes. A Mazda RX-8 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.