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Mazda
CX-8
KG·
2018-2023
suv-soft
Value
Price (AUD)
$25k-$50k
Body styles
5-door wagon (3-row, 6 or 7 seat)
Drivetrain
Front-wheel drive (G25 petrol, base D35 diesel), On-demand AWD (i-ACTIV, most diesels and later G25 AWD)
Origin
Japan
Built in
Japan
Overview
The CX-8 (KG, launched in Australia 1 July 2018) is Mazda's three-row, seven-seat (or six-seat captain's-chair) soft-roader - essentially a stretched, narrower-track CX-5 sharing the same monocoque platform, SkyActiv drivetrains and conventional six-speed torque-converter automatic (no CVT, no DCT - a genuine reliability advantage over many three-row rivals). It launched diesel-only in Sport and Asaki grades with the 2.2 twin-turbo SkyActiv-D (D35), then added the 2.5 SkyActiv-G naturally aspirated petrol (G25) as the value entry point. IMPORTANT for buyers: the 2.5 turbo petrol that appears in the US CX-5 and the CX-9 was NOT offered in the Australian CX-8 - the AU range is only the G25 NA petrol and the D35 diesel. The petrol G25 was front-wheel drive at launch with i-ACTIV AWD added across the range from the 2022 update; the diesel was available FWD or AWD. The smart used buy is a serviced G25: timing-chain, naturally aspirated, no DPF and very robust. The D35 diesel is torquey, tows 2000kg and is frugal on the highway, but it is the variant to scrutinise hard - it shares the SkyActiv-D's oil-dilution / 'high oil level' DPF behaviour, intake and shutter-valve carbon coking, and was caught by the 2018 diesel ECM/DPF recall (REC-000894). Range-wide Mazda traits apply: the dated MZD Connect infotainment, reversing brake groan, and thin paint that chips on dark colours like Soul Red.
Engines & variants
2.5L SkyActiv-G petrol (G25)
Engine
2.5L SkyActiv-G high-compression direct-injection naturally aspirated petrol I4 (with cylinder deactivation)
Config
I4 NA
Displacement
2488cc
Power
140kW @ 6000rpm
Torque
252Nm @ 4000rpm
Drivetrain
FWD (AWD added from 2022 update)
Economy
8.1 L/100km combined FWD (real-world ~9-10.5 in a heavy 7-seater)
Tow (braked)
1800kg
Tow (unbraked)
750kg
Transmission
6AT
Timing chain / belt / gear
Timing chain (no scheduled belt replacement)
Pros
- Simple, tough naturally aspirated petrol - no DPF, no turbo, no regen worries
- Timing chain and a proven conventional 6-speed torque-converter auto (not a CVT/DCT)
- Cheapest CX-8 to buy and run; the value pick for short-trip / city families
- Same robust SkyActiv-G as the CX-5 with a long track record
Cons
- Only 140kW/252Nm hauling a ~1900kg three-row body - works hard when fully loaded or on hills
- FWD only until the 2022 update; lower 1800kg tow than the diesel's 2000kg
- Direct-injection intake-valve carbon possible at high km
- Real-world economy is thirstier than the diesel, especially around town
Known problems
low
Cylinder-deactivation lifter / engine-mount vibration
The 2.5 SkyActiv-G uses cylinder deactivation; as the deactivation hardware and the fluid-filled engine mounts age, owners can notice minor idle vibration or a faint drone. A mount losing its damping fluid is a common, cheap-to-fix vibration source.
Fix: Replace the failed engine mount(s); only investigate deactivation hardware if a fault code is present.
low
Direct-injection intake-valve carbon
Like most direct-injection petrols, carbon can build on the intake valves over time (no port-injection wash), causing rough idle or minor misfire at high km.
Fix: Walnut-blast / intake clean if symptomatic; quality fuel and regular oil changes slow it.
low
Reversing brake groan / squeal
A widely reported groan or squeal from the brakes when reversing, shared with the CX-5/CX-9; almost always cosmetic noise rather than a fault.
Fix: Pad anti-squeal shims, clean and lubricate caliper slides; many owners simply tolerate it.
2.2L SkyActiv-D twin-turbo diesel (D35)
Engine
2.2L SkyActiv-D twin (sequential) turbo common-rail diesel I4 with DPF
Config
I4 twin-turbo
Displacement
2191cc
Power
140kW @ 4500rpm
Torque
450Nm @ 2000rpm
Drivetrain
FWD or on-demand AWD (i-ACTIV)
Economy
6.0 L/100km combined AWD (real-world ~6.5-8.5)
Tow (braked)
2000kg
Tow (unbraked)
750kg
Transmission
6AT
Timing chain / belt / gear
Timing chain (no scheduled belt replacement)
Pros
- Strong 450Nm low-down torque - the engine the heavy 7-seat body really wants
- Genuinely low highway fuel use and long touring range; 2000kg braked tow
- Timing chain and a conventional 6-speed auto - no DCT/CVT to fail
- i-ACTIV AWD available; smooth and quiet low-compression diesel for the class
Cons
- Oil dilution / 'high oil level' DPF behaviour is well documented, worst on short city trips
- Intake, swirl/shutter-valve and EGR soot coking is common on the SkyActiv-D family
- Caught by the 2018 diesel ECM/DPF recall (REC-000894) - confirm it was done
- A poor fit for buyers who only do short urban runs - the regen never completes
Known problems
high
Oil dilution / rising 'high oil level' warning (DPF regen)
Post-injection during DPF regeneration washes diesel past the rings into the sump. On short urban trips the regen never completes, the oil level rises (a 'high oil level' warning), the oil thins and engine wear or damage can follow. A signature SkyActiv-D issue shared with the CX-5 diesel and addressed by Mazda recall REC-000894 (ECM/DPF software update plus a revised dipstick).
Fix: Confirm the recall ECM/DPF software update and revised dipstick were applied; do a 20-30 min highway run weekly; change oil early and monitor the level. Avoid for short-trip-only use.
high
Intake / swirl (shutter) valve and EGR carbon coking
Heavy soot coking of the intake manifold, swirl/shutter valves and EGR causes rough running, lost power and limp mode, and can break a shutter valve - posing a debris risk to the engine. Increasingly common on these as they age and on town-driven cars.
Fix: Intake/EGR clean or manifold replacement; address regen behaviour and short-trip use so it doesn't recur.
medium
Turbo wastegate / sequential-turbo and exhaust-pressure-sensor faults
The sequential twin-turbo system can suffer wastegate/actuator breakage and exhaust-pressure-sensor faults, causing boost errors, limp mode and power loss - the same hardware as the troublesome CX-5 diesel.
Fix: Diagnose and replace the affected turbo/wastegate or sensor; verify boost control on a test drive before purchase.
medium
Injector-seal leaks and oil-pickup strainer blockage
Leaking injector copper seals let combustion gases and soot past, and carbon can block the oil-pickup strainer dropping oil pressure - both reported across the 2.2 SkyActiv-D.
Fix: Reseal/replace injectors; clean or replace the strainer and sump if oil pressure is low. Insist on a full diesel service history.
Common problems (all variants)
low
MZD Connect infotainment glitches / dated system
The MZD Connect head unit feels a generation behind (slow responses, dated maps) and can suffer freezes, reboots, Bluetooth dropouts and ghost-touch; some units need a screen or head-unit replacement. A frequent complaint in CX-8 owner reviews.
Fix: Apply the latest firmware update first; replace the display or head unit if the hardware is faulty.
low
Reversing brake groan / squeal
Range-wide groan or squeal from the brakes when reversing, shared with the CX-5/CX-9 - widely reported, with no single definitive fix; almost always noise rather than a defect.
Fix: Anti-squeal shims, clean and lubricate caliper slides, quality pads; many owners simply tolerate it.
low
Thin paint / dark-colour chipping
Mazda paint is thin and chips easily, particularly on dark colours and the popular Soul Red Crystal; stone chips on the bonnet and front bar are common.
Fix: Paint protection film up front; touch-up or respray affected panels.
high
Takata airbag recall (early build / regional supply)
Mazda was part of the industry-wide Takata airbag campaign; while most KG CX-8s post-date the worst affected stock, any car with replacement or imported parts should be VIN-checked, as a faulty inflator can deploy with metal fragments.
Fix: Run the VIN through Mazda Australia / the Takata recall portal and confirm no outstanding airbag recall before purchase.
low
Erratic gauges / electrical earth and BCM niggles
Owners have reported odd electrical behaviour such as an erratic tachometer needle with sluggish response, or wipers parking in odd positions - usually traced to poor earth points or body-control-module quirks rather than mechanical faults.
Fix: Check and clean earth points; reflash/replace the BCM if a fault is confirmed; diagnose before replacing major parts.