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Transmission and drivetrainPart report

2019 Mazda CX-9 Transmission and drivetrain Problems

Complaints
5about this part
Share
9%of 53 total for the year
Median mileage
—not reported
Trend
Not enough dataFewer than 15 complaints, too few for a reliable trend.

NHTSA recorded 5 complaints about the transmission and drivetrain of the 2019 Mazda CX-9, 9% of the 53 complaints for this model year.

Fewer than 15 complaints name this part, so treat the figures as a rough indication only.

Example complaints

Selected from NHTSA records; personal details are removed. They are consumer reports, not findings.

“2019 CX-9 GT, 30K miles, in August found coolant leaking under the car. This was 5 months past the warranty (but only 30K miles!). After doing research online, I found this is a massively common issue with all engines from several years encompassing 2019, where the coolant leaks due to a cracked cylinder head. There is a TSB from Mazda, which requires replacement of the engine, once the crack is developed. I immediately called Mazda corporate on 8/15/2024 and opened the case with them. …”

NHTSA complaint #11620217, filed 2024-10

“The engine cylinder head developed an internal coolant leak, allowing coolant to enter the combustion chamber. This caused engine overheating and smoke coming from the tailpipe while driving. A dealer performed a coolant pressure test confirming coolant leaking into the combustion chamber, and wet/dry compression testing on all 4 cylinders showed low and inconsistent readings consistent with cylinder head coolant intrusion (Cylinder 1: 105/125 psi, Cylinder 2: 115/125 psi, Cylinder 3: 110/175 psi, Cylinder 4: 160/190 psi). …”

NHTSA complaint #11749615, filed 2026-07

“The engine developed a sudden coolant leak on the rear of the engine. A warning comes up stating that the car could overheat and lose power. After a few minutes and no sign of the car overheating, the car loses power and slows down on its own. The car has not yet been seen by the dealer or a repair shop due to no appointments available. Mazda USA has issued a TSB stating the issue with the engine and they state that a design flaw causes the cylinder head to crack because of the external forces from the exhaust system over bumps. …”

NHTSA complaint #11525329, filed 2023-06

Related service bulletins

Transmission and drivetrain: other model years

YearComplaintsShare of year
202219%
2021513%
2020211%
201959%
20181310%
201747%
201698%
201539%
2014713%
201357%
2012188%
20112515%
20102312%
2009610%
20082716%
20071214%

Other parts of the 2019 Mazda CX-9

Engine
23 complaints
Other or unknown
14 complaints
Electrical system
7 complaints
Suspension
4 complaints
Back-over prevention (rear camera)
3 complaints
Body and structure
3 complaints
Visibility (wipers, defrost, mirrors)
3 complaints
Brakes
2 complaints
Forward collision avoidance
2 complaints
Fuel system
2 complaints
Steering
2 complaints
Seats
1 complaints

← All problems reported for the 2019 Mazda CX-9

About this data. Data from NHTSA (ODI) complaints, recalls, TSBs and investigations, updated Oct 30, 2026. Complaints are unverified consumer reports and may be duplicated or inaccurate.

To check a specific vehicle for open recalls, use its VIN at nhtsa.gov/recalls. Methodology