What 52 owners told NHTSA about the 2019 Mazda Cx-90 Phev

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.

NHTSA ODI 11749615

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)

NHTSA ODI 11745033

- 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.

NHTSA ODI 11714720

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

NHTSA ODI 11690498

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?

NHTSA ODI 11670073

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.

NHTSA ODI 11651264

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

NHTSA ODI 11645310

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.

NHTSA ODI 11597741

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.

NHTSA ODI 11594259

Started with rough idle then got overheating msg on dashboard. After the diagnostics they found cracked cylinder head and quoted $6000 for replacement. Called Mazda USA and they denied our claim. Car is under 5yrs old & around 74k. While working on the car they noticed the turbo needed it to be rebuilt. Another $2k. There is TSB out for this and it’s a known problem, lot of others having/had same issues. Never had a car that needed an engine replacement even before car is paid off.

NHTSA ODI 11592956

In June of 2022, Mazda issued a TSB for an engine flaw that cause coolant to leak in to the engine and significant overheating occurred. This overheating causes the head to warp. The TSB states that the only repair for this is a newer model engine. This happened to my Mazda CX9 and quite a few more. There are class action suits currently ongoing. Mazda never made its owners aware of the TSB. The car can shut down on the highway which is dangerous to all.

NHTSA ODI 11592579

Have been making repairs back to back since I bought it had to do four oil changes within that year then tires were completely worn electrical problems kept freezing spark plugs completely burnt discs were really rust car automatically turned off even though the battery is still good and still had gas had that happen twice and did more of a history search in it has had more complaints before every time try to take it to Mazda always be something with their system

NHTSA ODI 11589375

Large crack in cylinder head

NHTSA ODI 11575086

Mazda has an open TSB Technical Service Bulletin for this and many other Mazda's with the same engine- TSB-Collant Leaks at Cylinder Heads, Bulletin # - 01-013/21 issued 10/15/21 (CRACKED CYLINDER HEADS) My 2019 Mazda is right here on the list: Mazda Dealer claims I have to replace the engine at a cost estimated at $12,000 us dollars no offer or solution to repair the cylinder head which is upward of $5,000.00 us dollars. cars under there warranty are covered. Many models across the country are leaving people like myself stuck with a major engine issue and Mazda admitting they have a problem without stepping up and supporting and paying for this high repair cost to correct the issue. Enclosed is a snip of the actual TSB Mazda sent to all their Dealers. I've researched this Mazda engine and there's cars out there with any where from 25k miles - 100k+ miles with this same issue Should be a Class Action Lawsuit. recall and Mazda needs to be honest with this most sensitive matter APPLICABLE MODEL(S)/VINS US Spec.: 2019-2020 CX-5 SKYACTIV-G 2.5T vehicles with VINs lower than JM3KF******830243 (produced before Jun. 9, 2020) 2016-2020 CX-9 SKYACTIV-G 2.5T vehicles with VINs lower than JM3TC******422801 (produced before Jun. 9, 2020) 2018-2020 Mazda6 SKYACTIV-G 2.5T vehicles with VINs lower than JM1GL******523967 (produced before Mar. 25, 2020) Same engine has a class action lawsuit against Mazda for burring engine oil they both tie together.

NHTSA ODI 11564776

The car has only 41k miles on it and the engine warning light came on. I had the car towed to Mazda and now it won’t start and it needs a new engine. (Which is on back order for months). It is covered under the powertrain warranty but does me no good if I’m without a vehicle, and making car payments on a vehicle that isn’t running.

NHTSA ODI 11561805

The contact’s husband owns a 2019 Mazda CX-9. The contact stated that while the vehicle was at the dealer for a diagnostic test, she was informed that the head gasket was cracked, and fluids were leaking into the engine. The vehicle was not repaired due to the cost. Additionally, the message “Excessive Engine Temperature - Engine Output Will be Limited" was displayed. The vehicle was not included in NHTSA Campaign Number: 21V875000 (Fuel System, Gasoline). The manufacturer was made aware of the failure. The failure mileage was approximately 62,756.

NHTSA ODI 11561308

The engine is leaking coolant i will be putting a 3rd motor in this car due to other 2 motor also have a coolant leaking and running hot i have contact mazda and would not stand behind there car

NHTSA ODI 11541917

On the last week of May, my car started experiencing sputtering and stalling out problems. I made an appointment at Mazda dealership for june 6th.meantime my husband checked all fluids and coolant was low so we topped up. Car was being driven very limited due to safety concerns. Then While driving on the freeway my car displayed a “excessive engine temperature, engine output will be limited” immediately my car reduced speed from about 65mph to under 15 mph while having my whole family including myself and 4 children in the car. We almost got hit by several cars while trying to get over to the shoulder. Once pulled over to the shoulder my husband came and followed me home on the back streets. Once again checked fluids and coolant again was back low this time empty. So In a day it completely had no coolant left. When taken into Mazda dealership for the appointment, customer service was so horrible I ended up leaving and taking my car to a 3rd party service center. Was advised to have a Hydrocarbon test on cooling system that measured at zero, then advised to take it for a diagnostic due to the sputtering, stalling and coolant leak, where they ultimately determined the coolant was leaking into combustion chamber &/or intake system. Pressure test shows drop in pressure, no visible external leaks present. TSB# 01-002/23 pertaining to cylinder head assembly replacement. Now I’m waiting for my appointment at a different Mazda dealership on June 12th! Please help

NHTSA ODI 11526241

The engine developed a sudden coolant leak on the rear of the engine. A warning comes up stating that the car could overheat and lose power. After a few minutes and no sign of the car overheating, the car loses power and slows down on its own. The car has not yet been seen by the dealer or a repair shop due to no appointments available. Mazda USA has issued a TSB stating the issue with the engine and they state that a design flaw causes the cylinder head to crack because of the external forces from the exhaust system over bumps. The failure appeared all of a sudden with no warning lights or indications, it just started leaking a small amount of coolant one day. Now I'm waiting for Mazda USA to tell us how they are going to remedy this issue and provide assistance. According to their TSB this affects three different vehicle models with the same 2.5L turbo engine built from 2016 to 2020.

NHTSA ODI 11525329

My 2019 Mazda CX-9 Signature has developed a coolant leak at the back side of the engine that is consistent with Mazda TSB 01-013/21. Coolant leaks down onto the oil filter and the exhaust where it's burned off. Currently, I can drive the vehicle, but I need to refill the radiator and coolant reservoir. I'm concerned about this developing into a catastrophic leak that could seize the engine or cause a fire from contact with the exhaust. This vehicle is still under the warranty period of 5 years/60K miles. I will initially contact the dealer regarding this issue.

NHTSA ODI 11524109

The coolant was leaking due to a crack in cylinder. The car overheated and the coolant leaked into the engine. Mazda refuses to identify this as an ongoing issue with the Mazda turbo skyactiv models

NHTSA ODI 11508779

The contact owns a 2019 Mazda CX-9. The contact stated while driving 15 mph, she heard an abnormal noise. The contact stated no warning light was illuminated. The vehicle was not diagnosed or repaired. A dealer was not contacted. The manufacturer had been informed of the failure. The failure mileage was approximately 25,000.

NHTSA ODI 11428967