Mileage when the problem started
Owner reports
Selected complaints filed with NHTSA by 2016 Mazda CX-9 owners, lightly cleaned up (personal details are redacted by NHTSA).
The contact owns a 2016 Mazda CX-9. The contact stated that while driving at an undisclosed speed, the air conditioning became warm and the fan was abnormally loud. Additionally, the engine temperature gauge was high. The contact pulled over and refilled the coolant reservoir. The vehicle was taken to an independent mechanic who initially diagnosed that the water pump was faulty and needed to be replaced. However, when the contact took the vehicle back to the independent mechanic for the water pump replacement, the mechanic diagnosed that the cylinder head was warped and referred her to the dealer. The vehicle was not repaired. The dealer was made aware of the failure and informed the contact that there was no recall associated with the VIN. …
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.
15 minutes after getting a wheel bearing replaced at the dealer, my engine coolant high temperature warning came on (never before seen). This occurred while I was on the interstate with no safe place to stop. When I was able to safely stop, I called the dealer. They said bring it back. I was unwilling to drive that far so chose the closest Mazda dealer. They informed me I have a cracked cylinder and the coolant is leaking into exhaust system. I was told the only option due to the mileage on the car (134,000) is to replace the engine for $8,000. This appears to be a known issue so I am shocked that it wasn't being checked for prior to the problem.
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.
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. …
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. …
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. …
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. …
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. …
Traveling on the highway going on a road trip. Had vehicle inspected prior and no fuel system problems were noted. I was going 75mph with my family when there was a coasting feeling in the car. I looked and my check engine light popped on and my car immediately would not accelerate and we quickly lost speed. By the grace of God were we able to pull over safely! Code P0132 was the engine code and after an hour, the engine light went back off and we were able to keep a safe speed traveling home. After speaking with a mechanic and dealership, I learned that this was a common problem with the Denso fuel system. My vehicle was not included in a recent recall that included a different year of my vehicle. …
Engine complaints in other CX-9 years
Frequently asked questions
How common are engine problems on the 2016 Mazda CX-9?
NHTSA has 71 complaints about the engine & cooling of the 2016 Mazda CX-9, 66% of the model year's 107 complaints.
Is there a recall for 2016 Mazda CX-9 engine problems?
No. NHTSA lists no engine & cooling recall for the 2016 Mazda CX-9. If the problem is widespread, a repair may still be covered by an extended warranty or a manufacturer service bulletin — ask a dealer.
At what mileage do 2016 Mazda CX-9 engine problems start?
Half of the complaints with a recorded mileage happened before about 60,000 miles, and 30% before 25,000 miles.
Is it dangerous?
Owners linked 1 crash, 0 fires and 0 injuries to engine & cooling problems on this model year. If you notice symptoms, have the car checked before driving further.
Source: U.S. National Highway Traffic Safety Administration (NHTSA) — owner complaints through October 20, 2026, recalls and defect investigations; fuel economy from the EPA. Complaints are unverified reports and are not proof of a defect. How we rate model years.