2016 Mazda CX-9 Complaint Log

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!

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

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.

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

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.

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.

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.

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

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.

Cylinder head coolant leak. No warning lights.

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.

Coolant sprayed on top of engine

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.

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.

Cracked cylinder head causing coolant to leak.

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.

Vehicle had a horrible coolant leak at the rear of the engine to find out the engine has a weak cylinder head and is known to break and leak coolant. The vehicle will need a new cylinder head or engine replacement.

My car has a cracking cylinder head and is leaking coolant.

A month ago, I experienced a coolant leak at the back of the engine compartment. Upon researching I found that the head was prone to crack at the turbo and produce the leak. I took to my dealer, and they confirmed that it was in fact a cracked head causing the coolant leak. They also confirmed it was a known Mazda problem on the 2016 and newer 2.5 liter turbo engines. The dealer fixed four in the last month and one on a car their salesman purchased that the head failed at only 2000 miles. I was quoted a cost of $5965 for cylinder head replacement. It seems extremely excessive for a new cylinder head and a more appropriate price for a completely new motor. If this is a known defect on this motor no matter the miles, it seems Mazda should correct this problem in or out of warranty.

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.

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.

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.

We noticed anti-freeze leaking from our car a couple of days ago and immediately brought the car to our local mechanic. The mechanic determined that one of the cylinder heads in the engine was cracked and was leaking anti-freeze. He said the car was unsafe to drive. He also told us that a TSB had been issued by Mazda for this problem ( Bulletin No 01-002/23, issued 02/10/23). This bulletin states "Residual stress generated during production in the cylinder head material may be greater than expected. The external force from the exhaust system when driving over bumps may cause unexpected force to certain areas of the cylinder head". Had we not noticed the leak, the engine could have overheated, causing the engine to seize at any time, any place. which could have led to a dangerous accident. An accident that could have occurred on a major highway and could have involved other vehicles as well. Our car has just under 80,000 miles, has been well maintained and garage kept. I do not understand why a manufacturing defect such as this - which could lead to engine failure is not a mandatory recall by the manufacturer. We should have been warned that this could happen and mazda should be responsible for the cost of the repair. It is an engineering design flaw of the vehicle!

My seat warmer caught fire and burnt a hole through the seat.

I started smelling coolant after exiting the vehicle from a drive. Coolant level was very low. Adding coolant did not last long. I could not see where the leak was. The dealership evaluated and determined I had a cracked cylinder head and the car is leaking coolant near the rear of the engine. This could cause the engine to seize should coolant get into the engine. The dealer (New Rochelle Mazda) explains the cylinder head needs replacing. The dealer also observed bad rear sway bar links. One was detached. The car is serviced at the same dealership every 5k miles. The car has approximately 85k miles. The cylinder head has been repaired by the dealer under the extended warranty. Safety risk was moderate as the car could have stalled on the highway. The component was inspected by the warranty company and dealer only. The only warning lamps that showed up once were both brake indicator lights came on and the climate control would not warm the car.

Vehicle “surges” at idle. 300-500 RPMS at a time. Sometimes the brakes hold and sometimes not. Have nearly been in 3 collisions the last 2 days because of this issue. The ECM codes indicate throttle body or TPS issue, both of which have been unfounded. Vehicle has 63,000 miles. Researching this topic online found that many others have had this issue with no associated safety recalls noted. I am hoping to bring light to this so someone doesn’t have to be injured or killed to have this rectified.

Engine head cracked. Known problem with a tsb issued

The car started to overheat so we added coolant and then the car started to stall had our mechanic look at it and he said the head gasket needs to be replaced. How is this not a recall

The vehicle has tire pressure monitoring system malfunction warnings and parking brake malfunction warnings even after taking to dealership to be fixed. Was told it’s a known problem by Mazda, should be recalled, but there were not any current recalls for the issue.

While driving, engine suddenly overheated due to coolant leak from cracked cylinder head. This was a known issue per the TSB 01-002/23. See attached. Vehicle only has 55k miles and has been maintained, only requiring oil change, topping off of fluids, and filter changes. Dealership has determined that it will require a completely new long block. Mazda USA is currently only willing to cover a small fraction of parts costs, requiring me to pay the remaining parts and all labor costs.

Car started running rough and losing power intermittently. After arriving home and parking the car, a puddle of coolant started at the rear of the engine. Online research indicates this is a known issue for the 2016 CX-9. Head gasket failure causes coolant leak from back side of engine at the head gasket. Coolant is still leaking 24 hours later without the car being run.

I have taken the Mazda CX9 since I bought it new to service at Mazda every 6 months or 5,000miles as suggested. Two years a new engine was required due to overheating and coolant problem which the service man noticed 5 months prior during service appointment but didn’t suggest doing anything. Now two years later new engine they installed overheated also.The Mazda has never been in a wreck of any sort. The Mazda has 86,000 miles on it only. How can a car have 2 engines fail in 7 years when it has been serviced there at the agency punctually as required?

Engine is leaking coolant. Took the car to Horne Mazda of Avondale dealership for inspection, was told coolant is leaking from cylinder head. Was told the engine overheated and both cylinder head and cylinder block warped and will need to replace the engine. I feel my safety and others were at risk because the car could have lost power and stalled in the middle of roadway at any time due to there was no symptoms of my car engine overheated, car was running as normal, no check engine light, coolant temperature gauge did not show it was overheating, no sign of engine loosing power, no smoke from under the hood, no sweet smell or any indication engine is loosing coolant and overheating while driving. It appears to be a slow leak because coolant reservoir still have coolant above minimum level. First sign of coolant leak was notice during first week of October 2023 when small amount of green fluid was found on garage floor, took car to dealer on Oct.12.2023 for inspection. MazdaUSA refused to cover engine replacement under paid Mazda Extended Confidence warranty (MEC), blaming it's owners fault for operating car while engine overheated and refused to provide written copy of inspection details.

The car has 75K miles on it and has always been maintained by either Mazda or independent garages. Engine overheating, took car to Mazda specialist and found the engine cylinder head is cracked. This is a known issue with this type of Mazda engine and Mazda has published a TSB which I attach. Car is unsafe to drive as coolant may leak completely at any stage and leave myself and family stranded. The cost of the fix exceeds $6,000!

As I am accelerating to merge onto the highway from an on-ramp, while the gas pedal is depressed, I will get a series of sensor alerts simultaneously (city brake malfunction, park assist malfunction, lane assist malfunction, etc.) and my gas pedal becomes non-functional at 60-70mph. It is terrifying especially when there is other traffic around my vehicle. This exact issue has happened 6 times within the past 12-18 months at seemingly random intervals but always when I am accelerating onto the highway at 50-70mph. I typically pull off to the side of the highway and turn off the vehicle. After letting it sit off for ~30 seconds, I turn the vehicle back on and all of the sensor alerts have cleared and the vehicle functions properly including the gas pedal and I am able to rejoin the highway. I took the car to the Mazda dealership in my state of Vermont a few months ago to have them diagnose and address the problem. They had never heard of this issue and were unable to find the root cause or fix it. Please help, this is dangerous!

The intercooler failed or failed cylinder head causing coolant leaking into the exhaust side and cause the engine to over heat.

Crack cylinder head

Coolant leak. Needs new motor to fix issue.

I just had my engine replaced due to a cracked cylinder head that allowed coolant to leak into cylinder #3 & #2.

Cylinder head crack/failure required the replacement of the entire engine on my 2016 Mazda cx9, the odometer was only at 85,000km. The crack Resulted in loss of coolant and overheating, the indicator on dash stating to pull over and shut the car off. This could have resulted in engine seizing if I was unable to safely pull over. This is a know issue by Mazda, the dealership has seen this issue before, there is lots of documentation online for this as well. There has since been updated parts to repair this issue, This should be a recall covered by Mazda. No car should require an entire engine replacement at 85,000km. This repair cost me $7700 out of pocket.

First radiator blew (after noticing the temp gauge higher than normal and fan running a lot), and when replaced, the 2016 Mazda CX-9 continued to leak coolant. Took it to dealership to find out engine cylinder cracked and head gasket. A simple google search finds that so many Turbo Mazda’s between the years of 2016-20 experienced this design flaw as well. Mazda would not cover any of it since the car was out of warranty. It costed me over $7,000 to repair radiator and engine.

My 2016 Mazda CX-9 2.5l Touring has approx 67,500 miles. I noticed the "sweet" smell of coolant after driving. The temp gauge was not showing signs of overheating. I checked under the hood and coolant level in radiator and reserve tank were normal. I also did not see any coolant leak/patches under the car. Few days later the car temperature gauge shot past the 1/2 mark. i stopped the care let it cool and checked under hood. radiator was empty but reservoir tank was still full. there were signs of coolant drips underneath car on the plastic cover below the area of the water pump (passenger front wheel side). waiting to have car assessed/fixed by mechanic.

Cylinder head had a crack in it and had to be replaced.

While driving on the freeway in stop and go traffic the engine warning light came on. A few minutes later the data screen stated that I needed to pull over immediately as my engine was overheating. I was on a stretch of the 5 freeway north of Oceanside with no exits for several miles. I pulled over and when the light went off I got back on the freeway to try to make it to an exit. I repeated this process until I was able to exit and pulled in at the first mechanic I came to. The vehicle was losing power at that point. Pulling in and out of the traffic was hazardous to both me and the other drivers. When they inspected my car, they determined that the coolant had been leaking for a significant period of time as demonstrated by the worn spot on the pipe it had landed on. Further inspection revealed a blown head gasket. When a new head gasket was ordered from the local Mazda dealership, the mechanic was surprised to learn that Mazda had four of these parts in stock as most dealerships would have to order the part. The Mazda service department told him that they had four head gaskets in stock because this happens pretty often. My research on this site and on the Mazda forum indicates that this is a known defect to Mazda. This vehicle has just over 56,000 miles on it. It is regularly serviced. There was no warning light prior to this incident, in fact, the blue light indicating the engine was cool had regularly appeared whenever I started the vehicle. I have the replaced head gasket in my possession, should inspection of the part be necessary. I have reported this issue to Mazda but have been advised it is unlikely they will reimburse me.

I took my car into the dealership and was told that I had a cracked cylinder head and the car is leaking coolant near the rear of the engine. This could cause the engine to cease should coolant get into the engine. The dealer (North Park Mazda, San Antonio) has confirmed this as the issue. I have received a video of the inspection from the dealership explaining the issue. The vehicle displayed a warning that it was overheating which is what prompted me to bring the vehicle in for service.

Head gasket blew in a 2016 Mazda CX9 while driving causing us to as safely as possible quickly get off the road from the middle lane of an interstate. This is from a known coolant leak in the cylinder head from service bulletin 01-013/21.

I am being told by the dealership service center that there is a coolant leak from the engine. A previous coolant look due to a hose was repaired but this is a separate issue related to the TSB for coolant leak at the cylinder head Bulletin 01-007/22

My engine head cracked whiling driving. sudden lost of complete power in houston texas at a 75mph speed. Was able to safely pull to the side. took it to the dealer where they confirmed it was a cracked engine head. Its a common issue with this model from 2016-2019 no warning light came on just lost 90% power. was able to restart and drive the 7 mins to the dealer.

Cracked Cylinder Head due to Coolant Leak - SB 01-013/21. This is a known issue with Mazda, yet it has happened with the vehicle being serviced regularly. This is happens directly after the warranty period and it is not being covered.

A strong coolant smell was noticed in the interior of the car and from the engine compartment. The diagnosis from the Mazda service facility was that there was coolant leaking from the head on the engine. Eventually this would have led to overheating of the vehicle which could have resulted in significant engine damage. The manufacturer has issued a technical service bulletin (TSB) for this problem. Cracking of the head that leads to coolant leaks is a known problem with this engine in several different models of Mazda including CX-5, CX-9, and Mazda 6. Our vehicle has remained in the shop since it was taken in on 11/8/2022.