2019 Mazda CX-9

The engine cylinder head developed an internal coolant leak, allowing coolant to enter the combustion chamber. This caused engine overheating and smoke coming from the tailpipe while driving. A dealer performed a coolant pressure test confirming coolant leaking into the combustion chamber, and wet/dry compression testing on all 4 cylinders showed low and inconsistent readings consistent with cylinder head coolant intrusion (Cylinder 1: 105/125 psi, Cylinder 2: 115/125 psi, Cylinder 3: 110/175 psi, Cylinder 4: 160/190 psi). Overheating creates a risk of sudden loss of power and potential engine failure while driving, including on the highway. The problem has been confirmed and diagnosed by an authorized dealer service center, and the manufacturer's technical hotline department reviewed the diagnostic findings directly. Warning symptoms (overheating codes and visible tailpipe smoke) first appeared at the time the vehicle was brought in for diagnosis. The manufacturer has an active technical service bulletin addressing cylinder head coolant leaks on this engine and model, along with a related warranty extension program, but has denied coverage for this repair on the basis that the leak is internal rather than external.

My 2019 Mazda CX-9 (VIN [XXX]) suffered catastrophic cylinder head failure on the SKYACTIV-G 2.5T engine at approximately 124,000 miles. The failure is consistent with Mazda TSB 01-013/21 (and successors 01-007/22, 01-010/24), in which Mazda acknowledged that cylinder heads on this engine can crack at the stud bolt hole and exhaust manifold flange due to manifold deformation and residual production stress. The first warning came in mid-May 2026, when the engine temperature warning illuminated during normal driving. An independent mechanic replaced the thermostat. The warning returned within a week, and the thermostat was replaced a second time with a higher-quality part. Four to five days later, the warning returned alongside more severe symptoms: the vehicle began jerking while in motion, a strong coolant-burning smell developed, and smoke was visible from the exhaust pipe upon shutdown. The vehicle became undriveable, had to be left at the failure location, and was towed. Safety risk: The jerking compromised vehicle control in traffic. Upon shutdown, smoke and burning coolant odor created fire and fume-exposure risks. Had this failure occurred at highway speeds or in heavy traffic, the sudden loss of engine power and erratic behavior could have caused a serious collision. Family members were in the vehicle during several escalating events. Confirmation: The vehicle was towed to an authorized Mazda dealership, where Mazda-certified technicians confirmed in writing that it is exhibiting the exact defect described in TSB 01-013/21 and that complete engine replacement is required. The diagnosis is formally documented and has been communicated to Mazda's warranty team. Mazda Customer Experience has been engaged since mid-May 2026 and acknowledged the issue. The vehicle is currently at the dealership and available for inspection upon request. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

- Coolant leak at cylinder head and turbo at only 63,000 miles. - Safety issue because no warning lamps or messages appeared and potential for car to overheat without coolant circulating in the system. Car could breakdown at worst time and location. Leaking coolant onto exhaust created potential for fire. - Problem has not been confirmed by dealer yet. Appointment is upcoming. - Symptoms of the problem were leaking coolant on ground, low coolant level, heater not working properly. - First appeared 1/29/2026.

1. What component or system failed or malfunctioned, and is it available for inspection upon request? ANSWER: Engine failure due to overheating. 2. safety & indicators: ANSWER: During evening rush hour traffic on a 3 lane highway my car went into a form of engine power saving mode while i had children in the vehicle; this was almost catastrophic form my family and the other vehicles around me. there was NO warning. there were no previous issues with my vehicle, this was unexpected. 3. technician review: this is a known issue with no warning: The technician inspected your vehicle and found a concerning issue with the engine overheating. They scanned the vehicle and found a trouble code P111A, indicating the engine coolant reached a temperature of 251.6 degrees Fahrenheit, forcing the engine into limp mode. Based on their experience, the technician believes the engine likely reached much higher temperatures, potentially causing internal damage to the engine block. After a thorough inspection, they found no external coolant leaks, but upon using a digital borescope, they discovered evidence of coolant entering and being burned off in Cylinder 3. Given the severity of the issue, the technician recommends replacing the entire engine to ensure the long-term reliability and extended life of your vehicle. Services completed: - Scanned vehicle and found trouble code P111A - Inspected engine and found no external coolant leaks - Used digital borescope to inspect cylinders and found coolant entering Cylinder 3 Recommendations: - Replace the entire engine

While driving on highway I get a message on my dashboard "High Engine Temperature/Engine Output may be limited" warning message. I pullover and see that the cooland is low. I wait for thee car to cool down and fill with coolant. After 5 minutes of driving, get the same message on dash. I had car towed to Martin Mazda in Delaware. Diagnosis is that I need a new EGR valve and new engine $13,000. How coincidental it has the same symptoms as described in TSB and manifests itself differently and not covered? I even had my vehicle towed to John Kennedy Mazda in Pennsylvania and diagnosis is coolant is leaking into my engine. Too much of a coincidence and I am not the only Mazda owner experiencing this. My car is part of the VIN for the Mazda Powertrain Warranty Extension Technical Service Bulletin 01-002/23 (Feb. 10, 2023). The Mazda Techs are trained to not diagnose as such not to be covered under the warranty due to the enormous economic strain it will put on Mazda corporation. Mazda gets around the class action suits by offering the Warranty Extension but not honoring it. Mazda needs to own up to their mistake and turn this Warranty Extenions TSB into an actual Recall. Will it take an actual stall of the Mazda affected vehicle on the highway causing deaths for some corrective action to be taken?

Failed water pump, blown head gasket, major coolant leak, and warped head causing the vehicle to overheat and die when coming to a stop. Vehicle died when stopped in construction on a highway and we were nearly rear-ended. Vehicle never showed check engine light and temperature gauge never showed that vehicle was overheating but significant damage was caused to the engine from “excessive temperatures.” Failure of warning signals allowed us to continue driving the car with a significant engine issue. Now the entire engine needs replaced at only 83,000 miles. Car was diagnosed by licensed independent repair shop. Additionally, front struts went out at approximately 40,000 miles making the car wobble at higher speeds. Was inspected and replaced by dealership.

Car coolant warning light came on for a short time 5 min after starting car, then would go off. During severely cold days it would come on then go off once the car was warm. On 2/25/25 the coolant warning light appeared and stayed on. The car made loud rickety noise, as it warmed up. After driving 2 miles the car coolant light turned red and began blinking. An alert appeared saying car over heating. The car was stopped and smoke came out of the car. The car leaked blue/greenish fluid. Overnight the car cooled. The next day the car continued making loud rickety noise driving to dealership. Dealership would not honor extended warranty for coolant leaks at the cylinder. The water pump cracked, with coolant leak also causing the cylinder to crack and leak oil. Dealership is suggesting total engine replacement. The car has gone through its normal servicing with no reported issues of coolant leak or depletion. The engine overheated in a span of 2 miles after being parked for 8 hours. The car was

I have a coolant leak that I have not been able to locate. Despite replacing the radiator, the leak persists. When I contacted the dealer to inquire about estimates for changing the water pump and timing chain, they advised that it would be more cost-effective to replace the entire engine, which would require removing the existing engine at a starting cost of $5,000, with a new engine costing approximately $6,000. They suggested that if I'm already experiencing issues, it might be better to either replace the engine or consider selling the vehicle and purchasing a new one. This response implies that the dealer might be aware of a larger underlying issue and prefers not to address it directly. Experiencing a coolant leak while on the freeway can lead to serious consequences. It can cause the engine to overheat, potentially resulting in significant engine damage and a complete breakdown. This not only poses a safety risk to the driver and passengers but also to other motorists due to the possibility of losing control of the vehicle.

2019 Mazda CX-9 Coolant Leak. 1st warning light just discovered on June 10, 2024. Dealership quoted not under warranty and will cost $14,000 to replace engine. Mazda has an open TSB Technical Service Bulletin for this and many other Mazda's with the same engine- TSB-Coolant Leaks at Cylinder Heads, Bulletin # - 01-013/21 issued 10/15/21 (CRACKED CYLINDER HEADS). Need Mazda to stand by their product and remedy impacted owners.