The car only has 70k miles on it. The engine started smoking under the hood. Immediately stopped to look. There was oil leaking but I could not see from where. I took it across the street to the Toyota dealership and had them look at it. They explained to me that there was a crack in the cylinder head and oil was leaking everywhere. Potentially causing a fire or even an explosion. The old was leaking all over the exhaust manifold and engine. I had my 2 toddlers in the car not long before this happened. This is extremely unacceptable. Currently Mazda is saying it will be 7200 to replace the engine and that cost is on me. I think that is absolutely absurd being there are only 70k miles on the car and I bought it brand new. I also kept up with all of the required maintenance.
NHTSA complaint #11755535 — an unverified report by a vehicle owner.
Crack in Cylinder Head of engine. Mazda has been sued about this and have issued recalls on turbo engines, but not on non turbo ones though its the same systemic design issue with these engines. Wants me to pay 5-7k out of pocket.
NHTSA complaint #11734993 — an unverified report by a vehicle owner.
The vehicle exhibits dangerous electronic malfunctions. A licensed technician (MV-113255) has confirmed a sporadic unintended acceleration defect where the cruise control 'decrease' button causes the vehicle to increase speed. Additionally, the vehicle repeatedly enters 'Limp Mode' in active traffic, causing a violent jerk and a total loss of acceleration while displaying a 'Smart City Brake Support' (SCBS) failure on the dashboard. An independent inspection also documented gross mechanical neglect, including loose battery terminals and a loose transmission bellhousing bolt, which may contribute to these intermittent electrical/safety failures.
NHTSA complaint #11732963 — an unverified report by a vehicle owner.
My cylinder head is leaking coolant. There is a well known and well documented issue with these cylinder heads cracking due to poor casting. This has become such a big issue that Mazda has even recalled the cylinder heads, BUT, only if the engine is equipped with Turbo. However, this issue is becoming enormous even for non turbo owners and is a huge safety issue as it can lead to overheating, stalling, and further damage to other components. I feel very strongly that it is time for Mazda to take some responsibility and extend the cylinder head recall to the non turbo engines.
NHTSA complaint #11733118 — an unverified report by a vehicle owner.
Car had a coolant leak due to cracked cylinder head that was defective from the factory it was fixed but now the car has engine problems again. Don’t want to keep having these issues in the future
NHTSA complaint #11729758 — an unverified report by a vehicle owner.
Per Mazda inspection, the back side of cylinder head #3 has an oil leak which is leaking onto the exhaust manifold. This creates a direct fire hazard as Mazda said they highly recommend not driving it for that reason. The Mazda dealership inspected and confirmed the issue, it in February 2026, with only 74,000 miles on the vehicle.
NHTSA complaint #11719756 — an unverified report by a vehicle owner.
I recently discovered a significant oil leak near the exhaust manifold of my 2018 Mazda 6 (2.5L NA), which has resulted in visible smoke and a burning oil odor. Upon taking the vehicle to the nearest Mazda dealership for a diagnosis, the service department informed me that the vehicle has suffered a cracked cylinder head. An active oil drip is visible behind the engine near the exhaust manifold immediately upon starting the car; consequently, the engine is leaking oil directly onto the exhaust components. This condition not only renders the vehicle inoperable but also presents a significant safety and fire hazard. At the time of this writing, my vehicle has only 46,996 miles and has been meticulously maintained. This mileage is well under the 60,000-mile powertrain threshold and represents a premature failure of a major internal engine component. There are numerous reports on Mazda owner forums describing this identical issue occurring in Mazda 6, CX-5, and CX-9 models. Some owners have even reported instances of minor fires or active burning under the hood due to oil contacting hot engine components. Mazda released Technical Service Bulletin TSB #MC-10241612-0001 (SA-037-23), which includes a redesigned cylinder head for 2018–2020 Mazda 6, 2019 CX-5, and 2016–2020 CX-9 models, demonstrating Mazda’s awareness of this design flaw. While the TSB currently only specifies the 2.5L Turbo engines and not the naturally aspirated variants, there is substantial evidence that this is a widespread defect across these model years, unrelated to owner misuse or vehicle mileage. Mazda should take full responsibility by issuing a formal recall or providing an extended warranty to cover naturally aspirated engines, thereby addressing this problem and preventing further safety risks.
NHTSA complaint #11709431 — an unverified report by a vehicle owner.
Cracked cylinder head causing oil leak and possible coolant leak. This is a known issue with this year and model. Mazda is trying to suggest the issue is only for the turbo engine, but the non-turbo engine is also defective, per countless reports online. I have a video from the service technician from the mazda dealership, but it is too big to upload.
NHTSA complaint #11694210 — an unverified report by a vehicle owner.
PCM ISSUE, passenger air bag issue, OCS wiring issue. infotainment system, transmission, and engine. Key fobs not able to be reprogrammed due to PCM issue
NHTSA complaint #11667949 — an unverified report by a vehicle owner.
Bought used with 47k miles. Two weeks later, took it to my mechanic for an inspection, they found a massive oil leak on the back of the motor. Took it back to the dealership and they diagnosed it as a cracked cylinder head, for which there is a known TSB and warranty extension. Unfortunately, the warranty extension only covers a coolant leak from the cracked cylinder head, not an oil leak. Thankfully, the dealership took care of me but had they not, I was looking at a $7k+ repair on a car I had owned for 2 weeks. In the TSB, Mazda acknowledges that there were both design and manufacturing flaws for the affected model years. In acknowledging the issue, they should have issued a recall for affected vehicles, not a simple warranty extension
NHTSA complaint #11659983 — an unverified report by a vehicle owner.
Coolant leaks at the cylinder head around the exhaust manifold causing my car to over heat. Also when my thermostat is set to the exact temperature for both sides my driver side blows cold and the passenger side blows hot
NHTSA complaint #11634788 — an unverified report by a vehicle owner.
Driving in traffic and the engine temperature warning appeared on dash. Dealer has confirmed there is a large coolant leak from the cylinder head. Mazda released a technical service bulletin regarding the issue affecting Mazda6, cx-5 and cx-9, but I will have to pay for a head gasket replacement.
NHTSA complaint #11634029 — an unverified report by a vehicle owner.
Dear NHTSA, I am writing to submit a safety complaint regarding my 2019 Mazda 6 GTR. Below are the details of the issue: Vehicle Information: Make: Mazda Model: 6 GTR Year: 2019 VIN: [XXX] Problem Description: My vehicle began to overheat while driving. The vehicle has approximately 35,000 miles and has been meticulously maintained at authorized Mazda dealerships. Mazda Liberty is now asking me to pay approximately $10,000 for a new engine, while Mazda warranty declined to provide support, as I am two months past the warranty period. I have discovered that there are numerous complaints similar engine issues with Mazda vehicles, specifically related to coolant leaks and cylinder head cracks. Incident Details: Date of Incident: [XXX] Mileage at Incident: 35,000 miles Symptoms: Overheating, engine seizure Actions Taken: Topped up coolant, visited local garage and authorized dealership I believe this issue poses a significant safety risk, and I am seeking NHTSA's assistance in investigating this matter. Thank you for your attention to this serious issue. Sincerely, [XXX] Cell: [XXX] Email: [XXX] INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)
NHTSA complaint #11628947 — an unverified report by a vehicle owner.
Cracked cylinder head near the exhaust manifold. Created a large oil leak. Oil on the exhaust is a fire hazard. After one quart of oil loss a low oil level light comes on. This is a reported problem. One version of the engine I have has a Mazda TSB and an extended warranty. TSB 01-0022/23 A local repair shop has diagnosed the problem.
NHTSA complaint #11627463 — an unverified report by a vehicle owner.
The contact owns a 2017 Mazda Mazda6. The contact stated while driving at slower speeds and depressing the accelerator pedal, there was a delay before the vehicle responded. Additionally, the contact stated that after refueling the vehicle, the contact became aware of a fuel leak on the driveway. The vehicle was taken to an independent mechanic to be diagnosed and the contact was informed that the fuel tank was rusted and the fuel sending unit needed to be replaced. The local dealer was contacted, and the contact was referred to the manufacturer for assistance. The vehicle was not repaired because the warranty had expired. The manufacturer was made aware of the failure. The failure mileage was approximately 50,000.
NHTSA complaint #11624935 — an unverified report by a vehicle owner.
My car has stalled out on me 6 times in traffic and wouldn’t restart for hours. I took it to the Mazda dealership and they told me nothing was wrong but it continues to happen. I need something done as soon as possible
NHTSA complaint #11616978 — an unverified report by a vehicle owner.
Cracked Cylinder Head. At 50,400 miles. This is far too common of a problem for such a new car with so few miles. I have seen many similar reports online. My mechanic was baffled. This is a $5k cost AT LEAST. Mazda has a history of not covering these defects. And it IS a defect, not a simple wear and tear issue. A cracked cylinder head can eventually lead to engine failure, so it is dangerous to drive with it. The problem HAS been confirmed by an independent service center. I got a oil pressure warning sign.
NHTSA complaint #11616489 — an unverified report by a vehicle owner.
The contact owns a 2018 Mazda 6. The contact stated that while merging onto a freeway the vehicle did not accelerate while pressing the accelerator pedal, lost automotive power. After turning the engine off and back on the vehicle operated as normal but later while driving approximately 65 MPH the failure had reoccurred while attempting the pass a semi-truck on the freeway. The check engine warning light had also illuminated and the vehicle was eventually towed to the local dealer who was unable to determine the cause of the failure. The vehicle was not yet repaired. The manufacturer was not yet contacted. The failure mileage was 67,000.
NHTSA complaint #11607569 — an unverified report by a vehicle owner.