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2018 Mazda CX-9: engine and transmission complaints

VERY HIGH COMPLAINT SIGNAL
68%
82 of 121 relevant owner complaints are about the engine, transmission or fuel system

68% of relevant owner complaints filed with NHTSA on the 2018 Mazda CX-9 are about the engine, transmission or fuel system. Well over half of everything owners reported is the drivetrain. That is a severe model-level pattern; every model year we track at this level has a documented failure behind it.

Worse than 90% of the 1,230 model years we track (2010–2023).

Excludes 5 airbag, lighting and seat-belt recall complaints that would otherwise mask the signal (unadjusted: 65%).

NHTSA data checked September 13, 2026
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Drivetrain complaints
82
engine, transmission, fuel
Total complaints
126
this model year
Fires reported
1
owner-reported
Recall campaigns
2
4 crashes · 2 injuries

Complaints by component

ENGINE74 · 59%
UNKNOWN OR OTHER19 · 15%
ELECTRICAL SYSTEM15 · 12%
POWER TRAIN13 · 10%
SERVICE BRAKES11 · 9%
FUEL/PROPULSION SYSTEM5 · 4%

The years either side

2010
28%
49 of 195
2011
26%
38 of 170
2012
21%
40 of 221
2013
39%
22 of 68
2014
47%
24 of 54
2015
63%
19 of 35
2016
74%
72 of 99
2017
80%
49 of 61
2018
68%
82 of 126
2019
47%
25 of 53
2020
too few complaints
2021
61%
22 of 38
2022
too few complaints
2023
too few complaints

Manufacturers fix things mid-generation. A bad year next to a clean one is common; the fix usually arrived in between.

Cleaner alternatives

Same car, a better year

Other midsize SUVs with no elevated signal in 2018

The percentage is each model year's drivetrain complaint share. No elevated signal describes the model year, not any one car; a well-kept example of a flagged model can still be the right buy, and any of these still needs an inspection.

What owners reported

ENGINE08/08/2026
I was driving home from work and may car started overheating out of nowhere. I was stuck in traffic and white smoke was exiting my exhaust. I pulled over and all of my coolant leaked out of my car. Took it the shop and they said I had a cracked head and need a whole new engine. I seen that there was a warranty sent out…
ENGINE07/15/2026
The cylinder head on this 2018 Mazda CX-9 (Skyactiv-G 2.5T engine) cracked, allowing engine coolant to leak and intermix with engine oil, causing loss of coolant and catastrophic engine failure. The vehicle became undriveable in the first week of November 2025 at approximately 125,019 miles and has remained inoperable …
ENGINE06/05/2026
My wife was driving the vehicle when the emergency lights started going off. She had to pull over because the car wouldn't run and said it was overheated. All the maintenance has been done to the car. We took it to the dealership and they said it is a cracked head and it is a known issue. They even issued a extended wa…

Three of 82 drivetrain complaints. The full report shows more, with quotes about the engine in the car you are looking at first.

Recall campaigns on this model year (2)

FUEL SYSTEM, GASOLINE:DELIVERY:FUEL PUMP
Mazda North American Operations (Mazda) is recalling certain 2018 Mazda3, Mazda6, 2019 CX-3, 2018-2019 MX-5, CX-5, CX-9, and 2019-2020 Mazda2 vehicles. The impeller insi…
ELECTRICAL SYSTEM:WIRING
Mazda North American Operations (Mazda) is recalling certain 2018 CX-9 vehicles. The wiring harness may disrupt electrical communications and disable the passenger front…

This does not say whether a particular car has an open, unrepaired recall. That depends on the VIN.

Before you buy a 2018 Mazda CX-9

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Experimental model-level information. This is not a vehicle inspection, vehicle-history report, financial advice or purchase recommendation. It describes patterns across a model year, not the condition of any individual vehicle.