2018 Mazda CX-9 Complaint Log

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.

- My 2018 Mazda CX 9 started stalling and jittering at idle and then eventually during slow driving. - Next day I got a check engine light, took to Mazda service center at the dealership I have been going to for last 6 years since I bought the car. - Service center diagnosed that there was a coolant leak through the cylinder head which seems to have cracked. - Further investigation indicated that this has been identified on many other similar Mazda engines and a Technical Service Bulletin had been issued by Mazda to Dealers. - On probing initially, dealership declined they were aware of any such problem. - The amount of repair for the engine replacement (cylinder head and other parts) is exuberant and is almost half of the value of my car, and is not expected for a low 44,000 miles car. - This had posed safety issue for my family since the stressed engine with leak in cylinder head could lead to fire and fatality. - I am awaiting response from Dealership and Mazda corporation case#[XXX] for a response especially when this issue has been filed under a class action lawsuit: [XXX] INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

Over heating /coolant leak

coolant leaks at cylinder head , Mazda of America knows issues but not willing to recall , they hava a bulletin number 01-002/23 . pls help

While driving on an interstate service drive in Michigan, my 2018 Mazda CX9 GT suddenly lost power and began flashing overheating warnings. I tried to move my vehicle to a safe spot while the warning and sudden loss of power was happening, which took a moment due to traffic flow and my family being in the car. I moved the car off the road, and let it cool. I slowly drove the car to a parts store to get coolant. Once the cooling system was filled, I brought the car home and began researching the problem. According to internet threads like Reddit this is a wide spread problem happening among Mazda vehicles with several law firms researching class action lawsuits. My car is stuck at the dealership until I can find $12,000 to fix it, and sadly there are hundreds more just like me according to sites like [XXX] and [XXX] [XXX] [XXX] [XXX] [XXX] [XXX] And includes a Mazda Service Bulletin which indicates that there are design faults in the original cylinder head that causes the issue and that repair techs should replace failed parts with the updated and redesigned cylinder head. [XXX] INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

Vehicle had bucking coming to a stop. Noticed coolant was l9w, and temp guage was fluctuating at a stop slightly. Brought it to Lester Glenn mazda in toms river NJ, service writer informed us it is the cylinder head, and that the repair is approx $11,000. Vehicle only has 85000 miles on it, and was told by dealer that there is nothing they will do. This is a known issue, with a TSB issued in 2021 due to a defect in design where the turbo charger is mounted to the cylinder head. At this point, we are requesting the manufacturer take at least part of the responsibility of the poor design they sold to the open market, that is clearly a safety hazard to my wife and 4 kids, 1 of which is an infant.

Approximately three weeks ago, a message on my dashboard said to pull over immediately. Your car is overheating. I pulled over to a nearby auto shop, which indicated that I was just low on coolant. They topped off the coolant, and everything appeared fine. Two weeks later, I got the same message on the dashboard, saying my car was overheating to pull over immediately. I pulled into a nearby auto parts store and purchased coolant for the vehicle. When I checked the reservoir, it was bone dry. I added coolant and drove the car home. The following day, I checked the reservoir to see if there was still coolant, but it was all gone. I scheduled an appointment with the Mazda dealer to have the car inspected. I also checked the Mazda Forum website to see if other vehicles of my make and model had similar issues since I had never experienced this before. I found that the overheating in vehicles of my make and model was a "known issue" with Mazda. When I took it to the dealer the next day, the service agent informed me that the "known issue" was only with the Turbo model. I explained that my vehicle is a turbo model. He said that Mazda did not have to cover any costs because no recall was issued, even though it is a known issue. Mazda is now refusing to cover the repair and has indicated that the repair and replacement of the engine will cost approximately $9800. If I had been alerted earlier, I would have been able to have the car repaired.

Engine is leaking coolant apparently due to a cracked engine block caused by a manufacturing defect in the casting. Mazda has a Technical Service Bulletin, subject:Leaks at cylinder head and the number is 01-013/21. But they refuse to help cover their mistakes and now we owners are stuck with replacing an entire engine out of pocket. Shame on Mazda

The contact owns a 2018 Mazda CX-9. The contact stated that while driving at various speeds, the engine started overheating within approximately 15 minutes of driving. The contact had to pull over and wait for a while to let the engine cool down before continuing to drive. The contact stated that there was a message that the engine was overheating and to stop driving the vehicle displayed. The vehicle was taken to the dealer where it was diagnosed that coolant was leaking into the cylinders due to a fracture in the cylinder head. The contact was unsure of the cylinders with the failure. The contact was informed that the engine needed to be replaced. The vehicle had not been repaired. The contact found a Technical Service Bulletin regarding the cylinder head failure. The manufacturer was made aware of the failure and confirmed that the VIN was not covered under the TSB and that the TSB had expired in 2023. The failure mileage was 76,000.

I purchased a 2018 Mazda cx9 from a local used car dealer several weeks ago. Check engine light came on after a few weeks for cylinder 3 misfire and there was a steep decline of the vehicle performance (hard start, rough idle, lower mpg, sluggish driving). Took it to Berge Mazda who charged me for diagnostics/spark plugs, and ignition coil. They informed me the next steps were a compression tests, fuel injectors and if that didn’t fix the problem then they wanted to strip down the engine to evaluate the cylinder head. At this point I decided to take it to my local mechanic who I trust, he diagnosed a cracked cylinder head. Now I’m stuck with a car I just bought that’s unsafe to drive needing a 6-8k repair. Upon further research there is a widespread problem with Mazda’s manufacturing of there cylinder heads on certain models (including the 2018 Mazda cx9). This is confirmed by TSB’s from Mazda along with a class action lawsuit recently filed. Upon more research on my vehicles history, I gathered that my vehicle was traded into Horne Mazda and then a couple days later auctioned to the used car dealer I bought it from. The fact that Mazda is selling off their own defective vehicles that are unsafe at auctions is absolutely disgusting and something needs to be done about it.

Mine Mazda 2018 CX9 had coolant leakage at 55K miles. Issue is with faulty cylinder head acknowledged by Mazda in below mentioned TSB. I open up a case with Mazda (File Number XXX). Dealer quoted 7500$ expense and Mazda is providing assistance of 3101$. I have always serviced at Mazda authorized dealership and this issue was never reported. TSB [XXX] INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

"High coolant temperature warning. Stop car at a safe place immediately " came up. Stopped car at a mechanic and diagnosed as coolant leak onto the engine.

My car started leaking coolant from cylinder, it is known issue for these models, unfortunately Mazda cooperation doesn’t cover the expenses, there is Service Bulletin about it, so basically so many car got affected or will affect from this problem. It is manufacturer fault, not about customer usage or mistake.

Due to the flawed engine design which is well documented for these engines, ours started leaking coolant and it was eventually discovered that the head had cracked, and we were forced to have the head replaced. This repair cost us approximately $7600. Our hope is that Mazda will eventually issue a recall.

Cylinder head cracked at 100k. There is tsb knowing that this is a problem. It even stats that it happens during Manufacturing there was a defect. Coolant is leaking out the back side of the motor. Causing a over heating conditions stranding my family on the side of the highway.

2018 CX9 with 74k miles. Took it back to the dealer where I bought it from and have an extended warranty. They are telling me the extended warranty denied the coverage for Coolant leak, engine replacement

The 2018 Mazda CX-9 has been experiencing significant engine coolant leaks, which are suspected to stem from a manufacturing defect. The coolant leaks appear to be primarily caused by a casting defect in the engine block or cylinder head, exacerbated by the pressure and heat from the attached turbocharger. These defects lead to coolant escaping from areas that are typically obscured behind the exhaust manifold and turbocharger, making early detection difficult without detailed inspection.

Car started leaking coolant, and running rough / stalling. Eventually overheated due to lack of coolant. Mazda dealer reports Cylinder Head crack as the root cause of the issue. Car has 106K miles - and seems to have the same problem as referenced in NHTSA 10232269 [XXX] ) Mazda has decided to decline to offer any financial assistance in the repair. Replacement cost for just the cylinder head (not a complete engine) was quoted by a Mazda dealership to be $6800 - $7200. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

My vehicle had a coolant leak st the cylinder head around the exhaust manifold. The problem was confirmed by an independent service. No warning lamps, message or other symptoms of the problem prior to the failure did not appear. The problem was detected because coolant was dropping from the powertrain to the floor. When tha catalyst was removed it was found broken due to the high temperature but the car never display a high temperature warning lamp and the temperature display remains in normal position. The car could get on fire since no warnings or signal of high temperature was registered. After the situation occurred, I found a Technical Service Bulletin (No 01-01321) from Mazda North American Operations regarding this issue but since the problem occurred after the powertrain warranty the dealer did not accept to repair it. The probability that my car could get in fire was high since no warning lamps were display.

I recently bought a Mazda CX-9 and noticed that my vehicle was slightly overheating. The coolant level was very low. I took it back to the dealership I bought it from and they confirmed that there was a crack in the cylinder head and are working on the repair. After further research, I am seeing this is common with these models. Mazda is aware but not taking responsibility.

Cracked Cylinder Head Verified by Mazda Dealer . Noted it seems to be a very common problem with Mazda cx9 2018 models and has Multiple TSB on issue so I kept very close eye on car and took it in as soon as I smelled burning smell suggesting a leak , before the car had the chance to overheat and put myself and kids in danger. My car is under 40k miles for a 2018 with consistent maintenance - this is known problem since 2021 and needs to result in a recall.

Mazda has a known technical service bulletin [XXX] which has numerous engine cylinder heads which leaks coolant causing the engine to overheat without warning. On new cars. Mazda knows it’s an issue and has not pushed this information down to its consumers. [XXX] INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

Engine coolant leaking due to cracked cylinder head, found by Mazda dealership service inspection and diagnostics. Powertrain warranty only covers this until 80,000 miles, our vehicle is 116,000.

At 102,000 miles I have a cracked cylinder head

Cracked cylinder head resulting in no heat, leaking coolant and risk of overheating and fire. Crack on backside of cylinder head near exhaust manifold bolts. Weight of exhaust manifold is too much for the cylinder head and results in a Crack around the bolt. Cylinder head was casted too thin at the factory resulting in the head no being able to support the weight of the turbo and exhaust manifold. Mazda is not covering the defect under goodwill when customer is outside of warranty even though it effects every 2.5 turbo engine made between 2015 and 2020.

My 2018 Mazda CX-9 developed a rapid overheating issue which was determined to be caused by a cracked cylinder head. This was a known issue by Mazda as noted in a technical service bulletin (Mazda TSB 01-013/21). I've been told by Mazda corporate and the Mazda dealership where the car is currently parked that this bulletin means nothing and will they will not cover the cost of repair. My extended warranty is also telling me that they will not cover the cost of repair because they don't cover damage caused by overheating. Even though The leak caused the overheating in the first place.

The infotainment screen has spider like frost inside the screen. I've checked and other models have had this same issue and have been recalled and repaired. My model year 2018 is suffering the same issue and MAZDA has lagged on this problem. Please put out a recall on this as it is a hazard when you rely on your navigation system and other components the screen assists with.

We noticed a coolant leak and took vehicle in for service. Told that engine has a Coolant Leak at Cylinder Head [XXX] . 5 year old vehicle, 56k miles. No other warnings. All maintenance has been previously performed as required. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

Went in to the mechanic to get a regular oil change and noticed a liquid slushing sound after starting the car up. Was informed that there is a major coolant leak somewhere in the car. Took it to Mazda dealership right away who confirmed that it is a cracked cylinder head. I got lucky that the car did not overheat on the road and happened to catch it in the nick of time. No check engine lights or low coolant lights came on at all.

As I was driving 26 mile trip to work I noticed a red light illuminated on dash indicating the temp was about 240-260. I pulled into the parking lot immediately turned car off. After work (8 hour shift) drove home temp stayed at 200-210. The next morning I took it to the mechanic I’ve used for years. He did a visual detailed inspection finding that the water or antifreeze in the radiator was low. The antifreeze in the over flow tank was about an inch or so above the “L” line. He said there may have been an air pocket in it, a leak, water pump or thermostat going out. Watch the fluid levels daily, if the lower again take it to the dealership where I purchased it (4 months ago with 106K miles on it). I do have a 3 year or 30,000 mile warranty through the dealership. 4 days later I was very observant watching the temperature gauge. It went up to 240 briefly, so I got home and had my ex-husband check it. Both the radiator and the overflow tank were bone dry. Topped off radiator with antifreeze and the overflow tank to the “F” line. Car had cooled and right before topping fluid started. There is no noticeable sign of a leak (smell, white smoke from exhaust, visible puddles of anything on the motor or the ground where I’ve parked. Today is Thursday 10/12 and I can’t get an appointment with dealership until Tuesday. I’ve been reading a lot online about this being a very repetitive issue. In some cases new engine replacement required. Mazda is well aware of not a few but NUMEROUS issues and complaints, a recall is needed for this situation. Right is right and fair is fair!!

Coolant leak in the 3rd cylinder, causing the car to overheat and cracking cylinder head, making inoperable.