Overall, the Mazda CX-9 is popular among its owners. But as with any vehicle, mechanical failures often lead to customer dissatisfaction. Since its introduction in 2007, the most common major issues for the Mazda CX-9, as tabulated by Car Complaints, include brake system problems, engine failures, and coolant system issues.
Overall, the 2012 Mazda CX-9 received the most complaints, but Car Complaints rates 2008 as the “Worst Model Year,” citing issues with the braking system as the main issue with both models. Complaints dwindled beginning with the 2017 Mazda CX-9 and appear to have remained low into 2020.
The Mazda CX-9’s engine failure
With a “Really Awful” label for Car Complaints’ severity rating of 10.0, engine failure comes in at No. 3 on Car Complaint’s list of issues with the Mazda CX-9. The most common solution for engine failure is to replace the entire engine at a typical repair cost of $5,000.
On average, Mazda CX-9 owners with failed engines experienced that failure at 99,250 miles. While this is the most expensive and severe complaint lodged against the Mazda CX-9, it’s also the most infrequent complaint, which is why it is No. 3 on the list.
Brake power boost unit failure
The most frequent Mazda CX-9 complaint is the brake power boost unit failure. Typically, this issue occurs at 67,100 miles and is resolved by complete replacement of the power boost unit at an average cost of $680.
Drivers experiencing a power boost unit failure may notice longer stopping distances, a brake pedal that is hard to push, and engine stall when brakes are applied. This could be dangerous and potentially lead to an accident if not repaired immediately. The frequency of this complaint puts it at No. 2 on Car Complaints’ list with a “Pretty Bad” severity rating of 8.0.
Water pump failure
No. 1 on Car Complaints’ list of Mazda CX-9 complaints with another “Really Awful” severity rating of 10.0 is water pump failure. This issue earns the top spot due to collateral damage. Often, when a Mazda CX-9 water pump fails, it leaks coolant into the engine oil and causes engine failure too.
On average this has occurred at 102,150 miles and has a typical repair cost of $3,990 for replacing the entire engine with a used one. Signals that a water pump failure is imminent include coolant leaks at the front of the car, low coolant levels, and high engine temperatures.
Is the Mazda CX-9 a bad choice?
Out of 26 midsize SUVs, Consumer Reports ranked the 2020 Mazda CX-9 fourth overall with a score of 86 out of 100 and most notably scoring five out of five for reliability. This earned the CX-9 a Consumer Reports “Recommended” rating as an affordable three-row midsize SUV.
For comparison, the Kia Telluride scored a 92, the Hyundai Palisade scored 87, and the Toyota Highlander scored 86, and all earned the “Recommended” rating as well.
On 87 octane gasoline, the 2.5-liter turbocharged inline-four cylinder engine is somewhat underpowered for its class with 227 hp, but the CX-9 makes up for it by producing about 50 lb-ft more torque than its rivals with 310 lb-ft.
Fueling the tank with 93 octane gasoline allows the engine to make an additional 23 hp and 10 lb-ft of torque. Consumer Reports recommends avoiding the higher-priced premium fuel as the modest gains in performance are hardly noticeable.
As tested by Consumer Reports, the 2020 Mazda CX-9 performed as it should even during the braking test, an area of concern in previous years. However, the brake pedal is still firm and stopping distances were long for its class.