2016 Mazda CX-9: engine failure

Filed Oct 31, 2026 · Engine · FL

**the federal safety agency 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 the federal safety agency investigate the reported engine problems, including overheating, cylinder-head cracking, VVT actuator failures, and the availability of replacement components. I also ask that the federal safety agency determine whether these conditions represent a safety defect that warrants further investigation or corrective action by Mazda.

Filed Dec 27, 2024 · Engine · NC

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

Filed Jul 10, 2024 · Engine · OK

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.

Filed May 24, 2024 · Engine · NC

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.

Filed Apr 11, 2024 · Engine · NJ

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!

Filed Dec 15, 2023 · Engine · AZ

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.

Filed Oct 27, 2023 · Engine · TX

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?

Filed Aug 11, 2023 · Engine · WA

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.

Filed Aug 1, 2022 · Engine · TX

2016 cx9, after reviewing online. Known issue with coolent and engine cylinder. Water coolent leak to engine head. Dealer asking 75k to replace engine. Mazda refused to acknowledge the known issue.

Filed Jul 15, 2022 · Driver assistance, Engine · TN

On 04/21/22, I took my car to the dealer after noticing antifreeze on our garage floor and a burning smell. NO check engine lights had illuminated. They proceeded to tell me that there was a coolant leak from head/block and cavity leak (something about channel pressure). They also stated this was a casting flaw during manufacturing of the engine. They told me I needed a whole new engine for $8,479.97! Mazda corporate refused to replace the engine at their cost because I had 64,575 miles on it and it was out of powertrain warranty. I called them and asked to speak to a supervisor and never heard from them. I called on 4/26, 4/27, 4/28, 5/4, 5/5 (5 times), 6/9, & 6/20. I finally gave up agreed to pay $7,479.97 (the dealer gave me $1,000 off). I received the car back on 05/20 and it would not start later that day. They towed it back to Mazda and they replaced the crankshaft sensor that was damaged upon install of the new engine. I received it back again on 05/31 and later in the day, the check engine light came on and the automatic braking system engaged while I was driving (thankfully only 40 mph). I managed to pull over in a turn lane before the engine died. I was so thankful I did not make it onto the interstate I was about to enter! Mazda came and picked me up and later got my car. They could not figure out why it was dying and finally got it to recreate it. They replaced another engine sensor and then drove it a lot to make sure it was truly fixed. I finally received my vehicle back on 07/07. I am afraid to take my car out of town and it makes me nervous it will die and automatically start braking again. They KNOW this is a manufacturer issue and they refuse to take responsibility. I am so disappointed in them. This is a huge safety issue. I am also lucky I didn't blow a head gasket before I took it into the shop the first time.

Filed May 18, 2022 · Engine · 134,000 miles · NY

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.

Filed Dec 31, 2021 · Engine · TX

Dealer diagnosed manufacturing defect that caused crack in head. {Which could lead to engine failure, and subsequent accident due to engine failure during operation.} Engine lost coolant. No overheating noted. No warning/error codes noted.