2016 Mazda CX-9 Owner Complaints

**NHTSA VEHICLE SAFETY COMPLAINT – ENGINE FAILURE AND UNAVAILABLE REPLACEMENT PART** I am filing this complaint regarding serious engine problems with my 2016 Mazda CX-9 equipped with the 2.5L SKYACTIV-G Turbo engine. My vehicle experienced significant engine problems, including overheating, diagnostic trouble codes P0014 (exhaust camshaft timing/VVT system performance) and P0303 (cylinder 3 misfire). Following diagnosis, the cylinder head was found to be cracked, requiring machining and replacement of the timing kit. Despite these extensive repairs and expenses, the vehicle continues to have unresolved engine problems, including rough idling. The vehicle has not been fully repaired because I cannot obtain the exhaust-side Variable Valve Timing (VVT) actuator required to complete the repair. I have been unable to locate this component, and Mazda USA has indicated that the part is not available through its U.S. or Canadian parts network. This leaves me with a vehicle that cannot be properly repaired due to the apparent unavailability of a critical engine component. I find it unacceptable that an essential engine component for a Mazda vehicle cannot be sourced through the manufacturer or its authorized parts network. The situation has resulted in significant financial hardship, prolonged vehicle downtime, and the inability to restore my vehicle to proper operating condition. I am concerned that the underlying engine and VVT-related problems may represent a broader safety and reliability issue affecting other owners of 2016 Mazda CX-9 vehicles equipped with the 2.5L turbocharged engine. I respectfully request that NHTSA investigate the reported engine problems, including overheating, cylinder-head cracking, VVT actuator failures, and the availability of replacement components. I also ask that NHTSA determine whether these conditions represent a safety defect that warrants further investigation or corrective action by Mazda.

NHTSA ID

11774862

Incident

Mar 2, 2026

We discovered the problem by accident -- pulled out of our garage and there was a coolant puddle on the garage floor. No dashboard warnings, no overheat messages, no visible symptoms before that. That's what makes this failure mode dangerous: it loses coolant silently, and you find out from a puddle or from an overheat, not from the car telling you. A Mazda dealership confirmed the failure during a multi-point inspection by one of their master technicians (September 2026): coolant leaking from the back of the cylinder head, no signs of coolant and oil mixing, and a scan showing no history of overheating. Their recommendation is cylinder head replacement. The vehicle is available for inspection on request. This exact failure mode is a known design defect on 2016-2020 CX-9s with the 2.5T engine. Mazda itself acknowledged it -- special service program CSP11 ("Coolant Leaks at Cylinder Head Warranty Extension," NHTSA doc MC-11011136-0001, issued October 2024). That program extended the powertrain warranty to 10 years / 120,000 miles for precisely this failure, covering vehicles produced before June 2020 -- which includes this one. Here's the part that gets me: my vehicle is in the CSP11 VIN range, and the defect was diagnosed inside the program's 10-year date window. But the odometer is past 120,000 miles, so coverage was denied. The owner notification for CSP11 didn't go out until November 2024 -- to original owners. I bought this vehicle used, and never received that notice, so the extension was effectively invisible to the person actually driving the car as it crossed the mileage threshold. A manufacturer-documented design defect shouldn't lose all coverage on a technicality for used owners. Cause: UNKNOWN. The crack is at the cylinder head stud bolt hole area, matching Mazda's own documentation (TSB 01-002/23). No maintenance schedule prevents a casting crack.

NHTSA ID

11769435

Incident

Sep 10, 2026

Cracked head cyclinder leaking. Unsafe to drive, coolant can leak into engine if not already. They are aware of it and extended a warranty for the issue in 2024. However people like me, my coolant didn't leak until this year 2026. There have been lawsuits on this issue, but they are still failing to address this issue. They created another part to replace the defected part which costs around $6000-$7000. Yes, took it to a Mazda dealer and confirmed the issue and they can fix but cost would be out of pocket. No warning at all. The only way this was discovered was the smell of the coolant leaking.

NHTSA ID

11768085

Incident

Jul 15, 2026

My car have a manufacturer engine defect that the company or corporation is not willing to fix. Only because I exceeded the warranty I call them (MAZDA) an told them that it wasn't under my control the these issues happened after the warranty expire. But they still refuse to help me.

NHTSA ID

11765988

Incident

Sep 20, 2026

Engine revs or surges while in park, possibly faulty throttle box

NHTSA ID

11757879

Incident

Aug 18, 2026

The cylinder head (which involves the engine cooling system) has a known manufacturer defect that affects all year/models of the Mazda CX-9 with turbo. The manufacturing defect poses a risk to motor vehicle safety in a group of vehicles or equipment of the same design and/or manufacturer. Specifically, the overheating and failure of the engine can occur at any time, without warning. This puts my family at risk of being stranded on a roadway, particularly because my car is often driven in rural areas. The manufacturing defect is significant and is acknowledged by Mazda: Mazda has offered owners a voluntary, limited, warranty extension (CSP11) of 10 years or 120,000 miles. The voluntary warranty extension is not sufficient because it is limited in duration while the safety risk can happen at any time after the warranty extension expires. The warranty extension essentially only applies to about half of the expected lifetime of the car. NHTSA should determine that a recall and repair should be issued by Mazda that does not expire. The engine is defective, poses a safety hazard, and Mazda has fixed the engine for subsequent models (starting in 2021), so a repair is available.

NHTSA ID

11734209

Incident

Apr 27, 2026

I own a 2016 Mazda CX9 Touring FWD (180k miles). Today my car was diagnosed with cracked cylinder head, resulting in coolant and oil leak from the head gasket. While there is a class action settlement about it where Mazda accepted the manufacturing defect, they do not cover the engine repair/cylinder head replacement because my car's mile is over 120k. If it is a manufacturing defect, why year/mile make a difference on the responsibility of the manufacturer? Mazda obviously sold defect vehicles to their customers, and driving these vehicles under this condition is very dangerous! Now, they are expecting me to pay more than $10,000 for a vehicle priced around $6,000!

NHTSA ID

11706610

Incident

Dec 22, 2025

In June of 2022 I started having a strong antifreeze/engine coolant smell inside the cab of my vehicle and also outside the vehicle. I had the car checked for a radiator leak, but there wasn’t one. I took my car into my local Mazda where they found that the engine coolant was leaking into the heads of the engine. Mazda kept my car for 5 months and repaired the problem, it cost me $4000 and they had added a 12 month 12,000 mile warranty for the parts. My car is a 2016 Mazda cx-9 at the time of the repair it had 70,430 miles on it. Now a few years later I am having the same issue with the coolant smell inside the cab and outside my vehicle, it goes into the shop for diagnosis on Monday November 10,2025. The car now has 118,000 miles on it. I had purchased an extended warranty for the car at the time of purchase but it had timed out a month before I took my car in for the first repair….please Mazda stand behind your vehicles I am a senior woman with very little income and I will not be able to pay out of pocket for this repair and I CANNOT afford a new car… I would like to get reimbursed for my out of pocket on the first repair and get my car repaired this time as well under a warranty.

NHTSA ID

11697196

Incident

Jun 30, 2025

Cylinder head crack. Combustion gasses leaking into coolant causing overheat. Combustion gasses bleeding into oil causing excessive crankcase pressure.

NHTSA ID

11695620

Incident

Oct 25, 2025

The contact owns a 2016 Mazda CX-9. The contact stated that while driving approximately 45-50 MPH, the vehicle suddenly lost motive power with white smoke coming from the front of the vehicle. The contact was able to get to the side of the road to inspect the vehicle and became aware that there was coolant splattered all over the engine compartment. The failure had occurred twice. The “WRENCH” symbol was displayed with the “Service Vehicle” message displayed. The vehicle was taken to the dealer, who diagnosed that the coolant pump and water pump were leaking, and the radiator needed to be replaced. The vehicle was not repaired. The manufacturer was made aware of the failure. The manufacturer opened for the failure. The failure mileage was approximately 148,000.

NHTSA ID

11687565

Incident

Oct 15, 2024

Mileage

148,000 mi

Smart City Break Malfunction warning light appears while driving. Simultaneously the tire pressure warning appears. Also, at the same time, the temperature reads -20 to -40 degrees. Yes, vehicle is available for inspection. Fearful that car could randomly break while driving putting myself and family in danger since there is a malfunction. Mazda service center says the problem can’t be reproduced so there’s nothing they can do. The problem seems to appear when the outside temperature is 60 degrees Fahrenheit or higher.

NHTSA ID

11656449

Incident

Jun 1, 2024

Engine failure with crack in the engine after a loss of coolant fluid.

NHTSA ID

11632664

Incident

Dec 19, 2024

Head gasket leaking and caused major engine issue at 89,000 miles. Mazda has known of this issue, but refuses to recall it.

NHTSA ID

11626600

Incident

Sep 26, 2024

While my wife was driving her 2016 Mazda Cx-9 Grand Touring on the freeway, many of the dashboard indicator lights came on warning her the engine was over heating and to pull over immediately. While she was attempting to move over to the shoulder, smoke appeared from underneath the engine hood which made it difficult to safely move over to the shoulder. She believed the car was on fire so immediately exited the vehicle along with her sister whom was pregnant. I arrived within minutes and noticed the engine compartment was smoking and coolant/engine oil leaking underneath the car. The car was towed to my local Mazda dealership where I was advised days later the engine needed to be replaced due to blown head gaskets. They advised the vehicle over heated causing oil and coolant leaking from cylinder head that is warped. This repair would cost $11, 179.29. Mazda service advisor also mentioned the radiator and lower/upper radiator hoses needed to be replaced. This repair would cost $2691.28. This incident could've resulted in serious injuries or death from a known issue with these engines by Mazda. It's only a matter of time before this failed engine turns into a fatality. Do the right thing Mazda and fix these engines. Your reputation is on the line.

NHTSA ID

11625077

Incident

Sep 20, 2024

Sudden and dramatic loss of engine coolant. Received a warning that engine was overheating, and to shut off engine. Quickly obeyed the prompt and found that most of the engine coolant had been lost due to a catastrophic failure of either the head gasket or head itself.

NHTSA ID

11622599

Incident

Oct 24, 2024

Vehicle failed to turn off the engine while in park and I was unable to lock vehicle while engine was still running. The ignition button failed to work.

NHTSA ID

11621833

Incident

Oct 24, 2024

Cylinder head coolant leak. No warning lights.

NHTSA ID

11617629

Incident

Aug 28, 2024

1. What component or system failed or malfunctioned, and is it available for inspection upon request? The entire electrical system is malfunctioning. All dashboard service lights (check engine, ABS, etc.) illuminate simultaneously, causing the vehicle to stutter and shut off while driving. The vehicle is available for inspection. 2. How was your safety or the safety of others put at risk? This issue has resulted in a dangerous situation, particularly when the vehicle lost power on the highway with my young children aboard. This sudden loss of control could have led to a severe accident. 3. Has the problem been reproduced or confirmed by a dealer or independent service center? Mazda’s service department has not been able to reproduce the problem despite multiple visits. I have provided video evidence, but no conclusive diagnosis or resolution has been achieved. 4. Has the vehicle or component been inspected by the manufacturer, police, insurance representatives, or others? Mazda’s authorized technicians have inspected the vehicle several times, but no substantial action has been taken. The vehicle has not been inspected by police or insurance representatives. 5. Were there any warning lamps, messages, or other symptoms of the problem prior to the failure, and when did they first appear? All dashboard lights come on simultaneously without prior warning. The symptoms have been random and intermittent over the past few months. Given the ongoing risk, I request an immediate replacement of my vehicle. Please confirm receipt of this complaint and provide a plan for replacement. Thank you for your prompt attention.

NHTSA ID

11613534

Incident

Apr 16, 2024

August 2nd I noticed a smell of Coolant coming from my car. I looked under my car and noticed it leaking green coolant. I took it to Mazda where they had it for 7 days to then give me a $6,300 estimate with possible added expenses. They diagnosed it as a cracked cylinder head and needs a gasket as well. I am a single mother and have work but I cannot afford that repair especially since Mazda is not going to honor there vehicle and what they stand by. With this issue with the coolant leak and the cracked cylinder the vehicle could have overheated and go into limp mode and come to a sudden stop with my children in the car while driving on the road. I could be hit as this puts my family at risk of injury while we go to school or work. Mazda has done nothing but tell me to submit a claim with customer service which I have. I had my case manager call me once and left a voicemail and I have called multiple times and have not heard back. There was no warning of this until I found forums and other stories that this unfortunately has happened to hundreds of Mazda owners.

NHTSA ID

11611282

Incident

Aug 2, 2024

Coolant sprayed on top of engine

NHTSA ID

11603263

Incident

Jul 4, 2024

Our 2016 Mazda CX 9 began leaking coolant and we took it to a shop who diagnosed it as coming from the cylinder head, requiring a very expensive repair or new engine. Luckily our engine did not sieze up while driving, but it easily could have with our baby and toddler in the car. Upon searching the internet I found countless reports from other CX 9 owners who experienced the very same issue at similar mileage ~50k-70k. There is a technical service bulletin for this issue, but they have not issued a recall. This very expensive repair is going to set us back significantly and is a financial burden we were not expecting from our well cared for vehicle. It seems Mazda knows about the issue and is unwilling to address it.

NHTSA ID

11601041

Incident

Jul 1, 2024

The contact owns a 2016 Mazda CX-9. The contact stated while driving at an undisclosed speed, the check engine warning light illuminated, and the vehicle started shuddering and overheating. The vehicle was taken to an independent mechanic who diagnosed the vehicle and determined that the failure was related to a cracked head gasket. The vehicle was not repaired. The contact related the failure with the Technical Service Bulletin: 01-03/21; however, the vehicle was not included. The manufacturer was not notified of the failure. The failure mileage was approximately 92,000.

NHTSA ID

11596496

Incident

Jun 19, 2024

Mileage

92,000 mi

Cracked cylinder head causing coolant to leak.

NHTSA ID

11593707

Incident

Jun 3, 2024

2016 Mazda CX-9 is leaking coolant from exhaust side of engine cylinder head. This issue has been confirmed by a Mazda dealership in North Charleston, South Carolina. The issue first appeared shortly after replacing the water pump (performed by the same dealership). The issue is known and documents on Mazda TSB 01-002/23 - COOLANT LEAKS AT CYLINDER HEAD. The safety of my family was put at risk as there was no indication of a cracked head until there was coolant leaking on the driveway. Should the car have overheated without the indication of a coolant leak, the car would have been placed in to limp mode. Prior to the leak, there were no warning lamps or messages indicating the issue. Further, the Mazda dealership did not detect the issue at the time of replacing the water pump.

NHTSA ID

11592348

Incident

Apr 17, 2024

The contact owns a 2016 Mazda CX-9. The contact stated that while driving at an undisclosed speed, the vehicle stalled. Several unknown warning lights illuminated. The contact stated after the vehicle cooled off, the was able to be restarted. The contact checked under the vehicle and stated that there was coolant leaking on the ground. The vehicle was taken to an independent mechanic, where it was diagnosed with a coolant leak behind the engine. The vehicle was not repaired. The contact related the failure to Technical Service Bulletin: 01-002/23. The dealer referred the contact to the manufacturer for assistance. The contact was unable to reach the manufacturer for assistance. The failure mileage was unavailable.

NHTSA ID

11591593

Incident

Apr 15, 2024