Mazda CX-9
3.7-litre V6 with direct injection and chain drive. Large SUV engine with linear power delivery.
Large Family SUV
The strong turbocharged engine moves the large SUV with authority. The direct steering is a pleasant surprise, but ultimately it's a comfortable touring car.
Engine Weaknesses 6
The water pump on the 3.7L V6 sits inside the engine and is driven by the timing chain. Failure lets coolant into the engine oil — rapid engine damage results. Replacement requires 12–15 labour hours.
Symptoms: Milky oil filler cap, rising coolant loss without visible external leak, overheating warning, sweet smell from oil
The AWD system's power transfer unit sits too close to the exhaust system and overheats. The factory-filled lifetime gear oil degrades into sludge. Mazda extended the warranty (SSP92).
Symptoms: Burning smell from gear oil, shuddering or juddering on pull-away, fluid seeping behind the engine
Brake booster failures are documented on the CX-9 TB. The brake pedal suddenly becomes very hard and stopping distances increase considerably. A safety-critical issue.
Symptoms: Extremely hard, barely pressable brake pedal, significantly increased stopping distance, hissing noise when braking
The power transfer unit (PTU) on the CX-9 sits too close to the exhaust system. The gear oil overheats and turns to sludge after around 50,000–60,000 km, causing noise and eventually complete PTU failure. Regular oil changes every 30,000 km can significantly delay failure.
Symptoms: Grinding or squealing while driving, burning smell in cabin, oil leaking from PTU breather, vibrations in corners.
The individual ignition coils on the 3.7L V6 fail, often due to oil contamination of the spark plug wells from ageing valve cover gaskets. Can affect individual or multiple cylinders.
Symptoms: Surging under load, check engine light with P030X, noticeable power drop, rough engine
The 3.7 V6 tends toward increased oil consumption at higher mileages due to ageing valve stem seals. Repair is labour-intensive as the engine requires substantial disassembly to access the valvetrain.
Symptoms: Blue smoke on cold start, dropping oil level between oil changes, oil consumption of 0.5–1 l per 3,000–5,000 km.
Vehicle Weaknesses 8
The CX-9 TB's AWD system is sensitive to neglected differential oil changes. Mazda recommends changing the oil on both the front and rear differentials no later than every two service intervals, as old oil promotes clutch damage.
Front brake discs on the CX-9 warp under heavy braking loads. Centrally rusted and warped discs have been found at around 55,000 km. After two resurfacing operations, replacement is due.
Without additional cavity wax and underside protection, CX-9 TB models develop corrosion on the underside after several years. Suspension components and cross members are particularly affected.
The automatic gearbox shows shuddering or delayed shifts, especially when downshifting. The cause is often degraded transmission fluid or adaptive map drift. Regular fluid changes and a software reset help in many cases.
The factory battery in the CX-9 TB has a noticeably short lifespan, sometimes under one year. Even replacement batteries sometimes last only two years. Quality branded batteries are advisable.
The CX-9's electro-hydraulic steering provides little road feedback and feels indirect. At higher vehicle weight and with all-wheel drive, handling deficiencies become apparent on longer motorway runs. Software adjustments have only partially improved matters.
The third row of this seven-seater wears disproportionately fast due to the entry and exit demands placed on it. Upholstery and the folding mechanism are put under heavy strain by frequent use. Stiff or squeaking hinges are common.
The heat shield between the fuel tank and driveshaft detaches on older CX-9s due to mounting corrosion. This causes rattling and flapping from the underside, particularly at higher speeds.
Reports & Tests
1056 owner complaints filed with NHTSA (2007–2015). Most reported: Brakes (416), Suspension (144), Airbags (139).