Coolant leak. Needs new motor to fix issue.
2016 Mazda CX-9
Owner reports · Recalls · Investigations
Similar to other model years
Owner complaints for the 2016 Mazda CX-9 do not stand out strongly from the model-year median of 61.
About this comparison →How this year compares
Owner complaints by model year
Compare all CX-9 years →Counts vary with age, sales and reporting. They are not failure rates.
What owners reported most
All reported categories
Tap a category to read its complaints. One report may name several components.
When problems were reported
Mileage at the reported incident
29 reports with mileage · 75 unknown
NHTSA’s mileage field refers to the reported incident, not necessarily the filing date. This shows report counts, not the likelihood of a failure.
What to inspect
Issues worth paying extra attention to based on owner reports.
- Engine. Review the 65 owner reports in this category and discuss these concerns during a pre-purchase inspection. Read reports →
- Electrical System. Review the 14 owner reports in this category and discuss these concerns during a pre-purchase inspection. Read reports →
- Service Brakes. Review the 11 owner reports in this category and discuss these concerns during a pre-purchase inspection. Read reports →
NHTSA owner reports · September 18, 2026 snapshot.
Engine complaints
65 reportsThe 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 ma…
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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!
I just had my engine replaced due to a cracked cylinder head that allowed coolant to leak into cylinder #3 & #2.
Crack cylinder head
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.…
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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 experience…
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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 …
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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.
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 …
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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.
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.
Car overheated. check front engine and could not see any visible leaks. check all around the engine and found coolant leaking from the back of the engine. confirm by dealer that is leaking at the cylinder head.
Official recalls
0No recalls in this snapshot.
Model-level recall history does not show whether a particular VIN is affected or has received a repair. Check a VIN with NHTSA ↗
NHTSA investigations
0No exact-year investigations in this snapshot.
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