Mazda CX-9 Common Problems (And How to Address Them)
Mazda CX-9 is a mid-sized 7-seater SUV whose sleek design and comfortable interior make it a popular choice among consumers. If you’ve set your eyes on a used CX-9, you’d first want to research about the vehicle’s known faults and how reliable it is. This will help you make a more informed decision.
Mazda CX 9 common problems include:
- Water pump failure
- Brake booster failure
- Transmission problems
- Cracked cylinder head
- Front-end squeaking or chirping issue
- Body control module failure
In this article, we’ll take a deep dive into all these frequently experienced issues by Mazda cx9 owners. We’ll discuss the best solutions to consider for each problem, cx-9 years to avoid, cx-9 reliability, and more.
Mazda CX 9 Common Problems
Here are the most frequently experienced problems by Mazda CX9 owners:
Water pump failure
One of the frequently reported issues in the Mazda cx9 V6 engine is complete water pump failure. The work of this pump is to keep water flowing through your vehicle cooling system.
Therefore, if it stops working, your car will start overheating. An overheating engine can then warp to the point that it is ruined. Therefore, keeping your cooling system in good working condition is important.
When the pump fails, coolant from your vehicle cooling system may find its way into the oil system as well as other engine components.
The coolant then mixes with the engine oil—a mixture that starts circulating throughout the engine, causing engine destruction
If your vehicle begins to overheat, we advise you to pull over, turn it off, and then let a qualified technician diagnose it for the underlying problems.
Because you can’t tell when your water pump will fail, we advise you to keep your crossover cooling system maintained. Also keeping an eye on the radiator temperature level will give you a heads-up on this occurrence.
Mind you, a lawsuit has been filed for the Mazda CX9 water pump. It alleged that the 2008-2015 Mazda CX-9 model years were equipped with a defective water pump that would fail prematurely.
Unfortunately, this lawsuit got dismissed, so there’s nothing to celebrate for the consumers.
Mazda continued selling their vehicles to owners despite this defect and didn’t even issue a recall for their affected vehicle. Neither did they compensate the owners of the defective vehicles.
Most owners complain about the bad design of the cx9, which necessitates the need to remove the engine during water pump replacement. That’s such a labor-intensive task!
Mazda CX 9 brake booster failure
The CX9s are also prone to master cylinder brake booster failing. This is such a serious issue as brakes ensure your safety while driving on the road.
Most owners who have faced this encounter explain that the key symptoms include:
- Brake pedal feels heavy and becomes quite hard to push
- A hissing sound comes out when trying to press down the pedal
- A short screeching sound when the pedal nears the car’s bottom.
- Other drivers experienced increased stopping distance and difficulties trying to bring their cars to a stop.
The issue was so prevalent that the government opened an investigation into braking problems from the 2010 and 2011 CX9 model years.
But before the National Highway Traffic Safety Administration (NHTSA) could continue with their investigation, Mazda quickly announced that they had found the problem.
They narrowed down the issue to the materials used for the brake boosters.
Mazda also agreed to extend their warranty coverage for the brake issue. This satisfied the NHTSA who decided to close the investigation in July 2014.
The boosters tend to fail internally. As a result, the brake system has no vacuum assistance and you will be solely relying on mechanical braking.
You’ll know something is wrong when you feel the brake pedal becoming quite heavy or you have to push it down—you may even be forced to stand on the pedal to make it pull up.
When faced with this issue, we advise you to immediately stop driving your vehicle and pull over as it is unsafe to drive. Get your vehicle towed to a mechanic for the brake booster replacement.
Unfortunately, these repairs aren’t cheap and you should expect to part with anything from $300 to $1250 (parts plus labor).
Cracked cylinder head
It’s also not uncommon for the cx9 engine to fail completely and require a replacement. The cause of the engine failure is usually a cracked cylinder head that causes the coolant to leak.
The coolant leak then causes the engine to overheat—resulting in engine damage and the need to replace it with a new one.
The issue is more common in the earlier models of cx9. However, it may also affect vehicle models up to 2020.
Some of the common signs of a cracked cylinder head include:
- Coolant smell
- Coolant leaks
- Coolant residue (greenish) on the oil filter or exhaust manifold
- Overheating/high engine temperatures
- Low coolant levels
- Check engine light
- White smoke coming from the exhaust
- Heater may stop blowing hot air
- Coolant and oil may mix
- You may experience rough idle
The absolute best way to confirm if you have a cracked cylinder head is to perform a leak-down test (most auto shops will charge you $100 to $200 for this test).
The issue of a cracked cylinder head and coolant leaks tends to be more prevalent when the vehicles hit between 50,000 and 100,000 miles.
It’s also worth noting that though this issue is frequently reported, not all cx-9s experience it.
Keep in mind that Mazda released a technical service bulletin (TSB) to address the issue. According to the latest TSBs, the cx9 models produced on/before June 2020 may suffer from cylinder head leaks.
The best fix for this problem is to replace it with a new, updated part.
However, if your vehicle is outside the warranty, the cracked head repair may cost upward of $5000.
Some owners were fortunate enough to convince Mazda and their dealers to cover the repair costs for the cylinder head outside warranty out of goodwill.
Front-end squeaking issue
A chirp or squeaking noise coming from the front of the vehicle is also a commonly reported problem in Mazda CX-9 vehicles. This usually happens when making a turn to the right or left at slow speeds.
The noise is caused by front strut mounts that require a replacement. The strut mounts simply attach the suspension strut to your vehicle. Moreover, it helps insulate vibrations and tire noise from your vehicle.
Front strut mounts usually come with a bearing or bearing plate, which serves as a steering pivot. These mounts tend to wear out with time and may start causing the noise you hear when turning.
Some of the key signs of worn strut mounts include clucking noises, loose, noisy, or stiff steering, vibration, tire wear, and tire alignment issues.
When you start hearing the front end squeaking or chirping noise, that’s a surefire sign that the mounts are worn and require a replacement. The repair costs for this issue should cost you around $200.
Note that Mazda has offered a TSB for this issue, which means they can cover repair costs provided your vehicle is covered by the warranty.
However, if you’re outside the warranty, you’ll need to do the repairs from your pocket.
Transmission problems
Transmission troubles are also a common thing in Mazda Cx9s. A troubled transmission may lead to hard shifts, transmission slips, shifting delays, vehicle shaking while driving, grinding during acceleration, whistling noises, and even burning smells from under the hood.
When the transmission system becomes warm, the issues become more noticeable as the vehicle tends to jerk/jolt into the next gear or hesitate to shift.
Software issues may cause hard shifting and slippage of your transmission. However, a faulty shift solenoid or valve body may also be to blame for these problems.
Software updates for the transmission controller from Mazda have helped resolve most of the owners’ automatic transmission system complaints.
However, in some cases, the updates didn’t work. Instead, the fix was a shifting solenoid testing/replacement, body valve replacement, or even a complete rebuild.
Note that transmission issues should be fixed as soon as possible. If you ignore them, they may affect your vehicle’s fuel economy and you may even find your cx-9 suddenly stops working.
You should also routinely inspect your cx-9 transmission system for tear and wear as recommended by the manufacturer.
Body control module water damage
Many CX-9 owners have also reported their body control module going bad due to water damage. It’s common for the cx-9 BCM to become wet and start to malfunction due to clogged sunroof drains.
When the drain gets clogged, water overflows the holding area at the front part of the sunroof and spills into the headliner. From there, it flows down the pillar covers.
Since the BCM is conveniently situated at the bottom of the driver’s side a-pillar, water easily flows into it and damages it.
As you may already know, the body control module (BCM) in your vehicle communicates with every computer fitted in your car. It helps actuate the relays for door and window locks, mirrors, air conditioning, and other electronic components of your car.
When the BCM begins malfunctioning, your vehicle electronics may experience trouble communicating smoothly.
Key symptoms to look out for include the electrical system behaving strangely. For instance, the warning lights on your dash may stay on, turn signals may stop working, and the door and window locks may malfunction.
When faced with this electrical issue in your vehicle (i.e., the BCM going bad), you will need to replace it with a new one. The cost for this part is anything from $300 to $400.
Also, we advise you to avoid parking under trees. Whenever you give your car a wash, be sure to open the sunroof and clean its rails and the surrounding areas. This will help prevent clogging that may lead to body control damage.
Mazda cx-9 years to avoid
The Mazda CX-9 years to avoid include 2008, 2010, 2011, and 2012 model years. These model years have the highest number of issues as documented by Carcomplaints compared to the other model years.
They have defects ranging from engine to brakes, transmission, and water pump.
The 2008 and 2012 models were the most affected. The former has more issues per mile that cost the owners more in repairs while the latter revved the highest number of complaints overall.
If you’re interested in learning more about common problems in Mazda vehicles, you might also find our articles on Mazda CX-7 common problems and Mazda CX-5 common problems helpful. These resources provide insights into the issues faced by Mazda vehicle owners.Conclusion
Despite being a spectacular and spacious 7-seater SUV vehicle, the CX9 isn’t without its fair share of problems. Most of the car owners have repeatedly complained about a leaking water pump, body control module malfunction, brake booster failure, front-end squeaking noise, and cylinder head cracking.
Now that we have discussed these issues and solutions to consider for each of them, you should be able to handle them when they arise in your cx-9. And if you’re planning to buy a used CX9, this knowledge about common problems will help you know which model years to avoid and ensure you get a reliable used Mazda CX-9 vehicle.