2018 Mazda CX-9

My 2018 Mazda CX-9 with the SKYACTIV-G 2.5T engine has been diagnosed with a cracked cylinder head, cracked exhaust manifold, and cracked turbocharger at approximately 88,000 miles. This is a known design defect documented in Mazda TSB 01-002/23 and addressed by Customer Service Program CSP11, which extended the powertrain warranty to 10 years/120,000 miles for coolant leaks at the cylinder head. The TSB identifies exhaust manifold deformation and residual production stress as root causes of the cylinder head cracking. In my vehicle, the failure has extended to the exhaust manifold and turbocharger, both directly mounted to the cylinder head in the same high-stress zone. The turbocharger on this engine is a coolant-cooled unit. As coolant leaks from the cracked cylinder head, the turbocharger is deprived of its cooling supply, leading to excessive heat buildup and eventual cracking of the turbo housing. The turbo damage is a direct consequence of the cylinder head defect Mazda has already acknowledged. CSP11 covers the cylinder head but does not address consequential damage to the exhaust manifold and turbocharger caused by the same defect. I am requesting the NHTSA investigate whether Mazda's remedy is sufficient and whether a formal recall is warranted given the risk of sudden engine failure at highway speeds.

The liftgate (trunk) opens sporadically. The system keeps trying to open the truck and it's causing a parasitic drain on my battery. I was stranded 2 hours from my home due to this. My trunk would sporadically beep three times, that is the only warning I received. There are safety recalls for other year of Mazda cx-9 but not my specific even though I am having the same issue.

My 2018 Mazda CX-9 experienced catastrophic engine damage after a radiator failure allowed coolant to enter the engine. The vehicle provided no dashboard warning, overheating alert, or coolant warning before the failure occurred. Modern vehicles are designed to alert drivers to overheating or cooling system failures. The lack of warning prevented me from addressing the issue and resulted in catastrophic engine damage. I believe this represents a potential safety defect in the vehicle’s cooling system monitoring and warning system.

The adjustable rails holding the rear left seat in place no longer latch. It is available for inspection. This is the most common place for a car seat in this car. In the event of a crash the seat would slide forward. The seat belt attaches to the seat so there would be little restraint on the rear passenger. The mechanic who attempted a repair stated Mazda does not sell this part, only sells a replacement for the entire seat, about $5000. There were no symptoms, when adjusting the seat the rail just stopped holding the seat firmly in place when the adjusting bar was released.

Passenger seat heater either had a grounding issue or shorted out, causing to seat to start smoldering and catching fire, destroying the seat. There has been recalls and lawsuits for this specific issue on this model in other years, but not for this model year.

Here the facts, bought a car out of state (Illinois) from Iowa with 130,131 miles on Sept 12th 2025, Mazda CX9, the dealer did not disclose any problems with the car, after 3 months of ownership, the car overheats on highway whit family including a [XXX] infant, white smoke under the hood and exhaust pipe, towed home, radiator was replaced, few days after that a coolant leak, vehicle was sent to an authorized Mazda dealership for diagnose, the technician told us, according to Mazda procedures, a cod P111A, the vehicle's engine reached unsafe level of temperature and the whole engine needs to be replaced because a cracked head cylinder. This problem is well known by Mazda because they addressed on a TSB01-002/23 and CSP11 extended warranty, there is a flaw in the design of the engine near the cylinders manifold area, that cracks the engine and requires a full replacement of the engine. its just a flaw in the design of the engine. This issue can appear at any point threatening the life of the occupants of the vehicle INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

my 2018 MAZDA CX-9 safety issue SCBS / SBS, LAS / LDWS, MASTER AND/OR HBC WARNING LIGHTS Forward sensing camera (FSC) stops functioning cause my car run rough even depress accelration and those light came on dashbaord -Forworad smart city brake support malfunction -smart brake system -front camera sensor malfunction

[XXX] 2018 MAZDA CX-9 GRAND TOURING 89014 MILES Date: 9/11/2025 To: Mazda North American Operations Attn: Customer Experience Center 7755 Irvine Center Drive Irvine, CA 92618 USA Subject: Formal Complaint Regarding Safety and Technical Issue – 2018 Mazda CX-9 Dear Mazda Customer Experience Team, I am writing to formally lodge a complaint regarding a serious safety and technical issue I have experienced with my 2018 Mazda CX-9. After a recent inspection conducted by Mazda Koch 33, it was brought to my attention that the engine wiring harness is defective and may potentially cause a fire or result in burns, posing a severe safety risk to me, my passengers, and others on the road. This issue is deeply concerning and unacceptable, especially considering Mazda’s reputation for reliability and safety. A fault in the engine wiring harness, particularly one that has the potential to ignite or burn, should be treated with the utmost urgency. It is troubling that such a critical component could present such danger. My vehicle has been serviced and maintained regularly, and I was not made aware of any recall or technical service bulletin that addressed this defect until the inspection. Given the nature of the defect, I believe this may be a manufacturer defect, and I request that Mazda: Immediately investigate and confirm whether this issue falls under an existing recall or known defect. Take full responsibility for replacing or repairing the affected wiring harness at no cost to me. Provide assurances in writing that my vehicle is safe to operate. Offer compensation or a loaner vehicle if the repair process renders my vehicle unusable for any period of time. Please consider this a formal request for immediate corrective action. I expect a prompt response within 10 business days of the date of this letter. If I do not receive a satisfactory resolution, I will be compelled to escalate this matter further through consumer protection agencies, such as the INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

Passenger side sun visor will not stay in place. Cannot lock it in up position, which means it droops. Causing sight of vision impairment.

I am submitting this recall request because my vehicle has experienced repeated incidents of a serious safety issue. While driving—most often on the highway—a warning appears that says “Smart System Brake Malfunction.” Immediately after, the car begins braking on its own without driver input. This has happened multiple times and, based on online reports, it appears to be affecting many Mazda vehicles across different models and years. Each time, I have been forced to pull over, turn off the car, and restart it to temporarily resolve the issue. This is extremely dangerous, especially at highway speeds, as it creates a high risk of rear-end collisions and sudden loss of vehicle control. When reported to Mazda, the concern was dismissed as a “sensor issue,” but the repeated nature and widespread reports suggest a potential systemic defect that requires urgent investigation and recall.

Cracked cylinder head/leaking coolant.

. In January 2024, I purchased a used 2018 Mazda CX-9. The vehicle ran well until [XXX], when I discovered an engine coolant leak. My mechanic diagnosed it as a known defect involving the cylinder head. My husband contacted Mazda Customer Service (CS), and they advised us to get an official diagnosis from a Mazda dealer. We brought the car to Orland Park Mazda, where a diagnostic confirmed the defect (report attached). We later received an email from Mazda CS saying that since our car was at the dealership, Mazda would take the lead in submitting the goodwill repair claim (email attached). When we followed up with Orland Park Mazda, they informed us that no one from Mazda CS had contacted them to authorize the repair. We relayed this to Mazda CS and gave them the direct number of our service advisor, Adrian. Mazda CS said they would follow up and get back to us within 48–72 hours. On a follow-up call, I spoke with Nancy at Mazda CS, who again told me that our case manager Cindy would contact us within 48–72 hours. Instead, we received an email denying the repair, stating the vehicle exceeded the 120,000-mile limit for the extended warranty (our vehicle has 133,500 miles). While our car is outside the warranty period, this is a textbook case of a well-documented defect covered under TSBs for the 2018 CX-9. Mazda has previously approved goodwill engine replacements for other customers well beyond this mileage. We are seeking fairness and consistency in handling known product defects. Our request is that Mazda approve the engine repair under goodwill coverage as they have in many similar cases. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

1. The navigation has a frosted crackle appearance framing the screen. It is difficult to read the navigation when needed. I know this has happened to other models of this vehicle and those were recalled and covered. 2. The brake senor keeps going off stating "SMART BRAKE SYSTEM MALFUNCTION". This goes off repeatedly while driving. 3. Then a second message pops up and reads "FRONT RADAR SENSOR SYSTEM MALFUNTION".

coolant leaking from engine block cracked cylinder head

Our Mazda CX-9, having roughly 86,000 miles, had catastrophic engine failure while driving. This is caused by coolant leaking at the cylinder head and around the exhaust manifold. This in turn caused a crack in the engine block. Mazda refused to fix this as it wasn’t a “recall” and only a tsb sent out. 1000 of people have reported this issue, causing failure while driving but Mazda will not recall the engines nor fix them under an extended warranty. After a 4 month battle with Mazda they refused to fix this in our car even though they know the engine is a bad manufacturing issue. A recall needs to be made and Mazda needs held accountable. Our exact cause was exactly what the TSB stated but Mazda stated our crack was not in the correct spot. They need a recall covering all engine block cracks due to faulty manufacturing

coolant leaks at the cylinder head around the exhaust manifold. Caused crack in the head. The Mazda 2.5t engine has this common issue that Mazda knows about. Mazda has a bulletin out but has not issued a recall. Car over heated and I was left stranded. Took car to mechanic who says I need to replace my entire engine.

Fan is not working and car is overheating when driving in traffic or low speeds - from forums this seems to be a common issue with this make/model and year

My vehicle was low on antifreeze. I brought it into the dealer and had them look at it. They told me there was an antifreeze leak inside the engine. I told them, I think there's a service bulletin on it. TSB-01-013-21 And there are updates to it. They told me that the antifreeze leak does not pertain to this service bulletin. I told them, how can that be? When it's an antifreeze leak with an engine that only has 66000 miles on it so far. I spoke to mazda customer service in California They said the dealer is trying to get some financial relief for me to replace a $10000 engine. Which they said is on back order till march 2025. I said how can this leak not be a problem when the engine is on back order, I feel that this should not have happened With a engine, that has 66000 miles on it? And it should be fixed free of charge because antifreeze leak is a known problem with these engines since 2016, and they never notified me to bring it in and have the defective part fixed Which causes the antifreeze leak. If they did that, my engine would not have blown and would not need replacement. I'm hoping they understand and do the right thing and fix this.

Steering makes knocking noises when turning. It happened suddenly with no damage to car to cause it. It was fine prior to parking, when the car was restarted and the wheel was turned knocking noise started. Mechanic found there is a tsb for this problem but no recall.

Engine cylinder head is leaking coolant. This is a known issue by Mazda as they have submitted a TSB on the issue but have yet to submit a recall. The leak causes overheating along with pollution of coolant fluid into the environment. The problem was diagnosed by a Mazda dealership. The leaking occurred before a light came on the dashboard. The light on the dashboard only came on once the engine began overheating.