Coolant leak into cylinder head, resulting in overheating and blown head gasket. Repair cost was $7k to resurface cylinder head and replace gasket. Repair did not fix issue, likely due to unseen cracks or warping to cylinder head. Will require rework, likely entire engine replacement, as the defect cannot be corrected.
2018 Mazda CX-9
Owner reports · Recalls · Investigations
More warning signs than most CX-9 years
Owner complaints for the 2018 Mazda CX-9 are substantially higher than 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
Limited mileage data: 15 of 127 reports include usable mileage. There isn’t enough coverage to show a useful chart.
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 75 owner reports in this category and discuss these concerns during a pre-purchase inspection. Read reports →
- Electrical System. Review the 15 owner reports in this category and discuss these concerns during a pre-purchase inspection. Read reports →
- Power Train. Review the 13 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
75 reportsThis weekend Mazda CX-9 started leaking coolant from the firewall side.
Driving the car home from work, the engine temperature gauge started to go up high. I added coolant that same night. Went to the dealership for a check up. I was told the coolant was coming out from the back of the engine and will need to partial repair the engine. Only 75k miles in the engine and that was an estimate cause I co…
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Driving the car home from work, the engine temperature gauge started to go up high. I added coolant that same night. Went to the dealership for a check up. I was told the coolant was coming out from the back of the engine and will need to partial repair the engine. Only 75k miles in the engine and that was an estimate cause I could need a brand new engine. Now I’m stranded with out a car waiting for a response. MAZDA should do a recall regarding that issue cause I’ve seen a lot of CX9s have the same issue. THATS NOT GOOD FOR RELIABILITY.
After owning this used vehicle for about 11 months, the engine temperature gauge indicated the car was running hot - about 240 degrees. After inspecting the vehicle at home, we added coolant to the system. This helped maintain engine temperature temporarily, but we noted over the next several weeks that the coolant was dropping …
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After owning this used vehicle for about 11 months, the engine temperature gauge indicated the car was running hot - about 240 degrees. After inspecting the vehicle at home, we added coolant to the system. This helped maintain engine temperature temporarily, but we noted over the next several weeks that the coolant was dropping rapidly. After inspection by a Mazda dealer, it was concluded that the cylinder head needed replacing.
I have a 2018 Mazda CX-9 with about 66,000 miles. I noticed a coolant leak when my SUV sat in my driveway. It was there each night after driving the SUV. I took the vehicle to a Mazda dealer who stated that the coolant leak is from a cracked cylinder head. A cylinder head should not crack in 4 years and only 66,000 miles. T…
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I have a 2018 Mazda CX-9 with about 66,000 miles. I noticed a coolant leak when my SUV sat in my driveway. It was there each night after driving the SUV. I took the vehicle to a Mazda dealer who stated that the coolant leak is from a cracked cylinder head. A cylinder head should not crack in 4 years and only 66,000 miles. This is a known Mazda issue for this year make and model.
I noticed a smell of antifreeze. After taking it back to dealership, I find out it has a cracked head. It has never ran hot.
The cylinder head failed causing a massive leak of engine coolant. This occurred initially at highway speeds which caused potential danger to myself and others around me as the car was required to pull over immediately. The problem was confirmed by the dealer and is known to the manufacturer as indicated by TSBs. The part was i…
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The cylinder head failed causing a massive leak of engine coolant. This occurred initially at highway speeds which caused potential danger to myself and others around me as the car was required to pull over immediately. The problem was confirmed by the dealer and is known to the manufacturer as indicated by TSBs. The part was inspected and replaced by a new, redesigned part at the owner's expense.
the cars engine makes loud rattling noise and slips gear. the vecicle jerks hard and feels as if transmission is slipping. car hesitates when i shift into gear, followed by a jerking and jolting into gear. my brakes are replaced frequently. mazda at 65643 miles on car found excess operating noise coming from engine coolant/water…
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the cars engine makes loud rattling noise and slips gear. the vecicle jerks hard and feels as if transmission is slipping. car hesitates when i shift into gear, followed by a jerking and jolting into gear. my brakes are replaced frequently. mazda at 65643 miles on car found excess operating noise coming from engine coolant/water pump due to internal bearing failing. they replaced the water pump. software (pyd8-18881-f) replaced. the vehicle has 74000 miles and has same problem. when stopped at a traffic signal it lunges forward at times. and shifts slow to fast gears. this problem is not resolved. the first time it was allegidely fixed was 22Dec2021 it is now 05Oct 2022
I purchased my 2018 Mazda CX-9 Grand Touring CPO with 39k miles and was sold the life time extended powertrain warranty through the dealership. The car now has 74k miles. While sitting idle at the school bus stop in my neighborhood waiting for my daughter the temperature gauge light comes on. I immediately drive home (exactly 0.…
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I purchased my 2018 Mazda CX-9 Grand Touring CPO with 39k miles and was sold the life time extended powertrain warranty through the dealership. The car now has 74k miles. While sitting idle at the school bus stop in my neighborhood waiting for my daughter the temperature gauge light comes on. I immediately drive home (exactly 0.3 miles) not going over 10mph back home, park call a tow truck company to tow it to the Priority Mazda dealership in Tysons Corner, VA from which I bought it. After a few days the mechanic calls and tells me there is a coolant leak and the repairs for the Cylinder Head should be covered under my lifetime extended warranty. A few days later I get a text message from the service rep that states. "Unfortunately, the extended warranty has denied coverage of the Cylinder Head, stating it to not be an internally lubricated issue....we need to fully inspect to determine what is needed (cylinder head or full engine due to overheating) Cost of teardown $1,432." After speaking to the service rep directly he then tells me the coverage was actually denied because Mazda put out a TSB on this known issue which voided my extended warranty on the cylinder head. This TSB bulletin no.01-007/22 was just issued 2 months before this happened. We should not be responsible for a known engine issue on Mazda's flagship car after purchasing an extended warranty for this very reason.
While commuting home on 8/19/22 my CX-9 began overheating and coolant temp. warning light illuminated on dash. This was a dangerous situation as I had to stop in the middle of traffic for fear of ruining my car and risk getting rear-ended and also navigate to the shoulder of the road. Took the car to the dealership where they co…
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While commuting home on 8/19/22 my CX-9 began overheating and coolant temp. warning light illuminated on dash. This was a dangerous situation as I had to stop in the middle of traffic for fear of ruining my car and risk getting rear-ended and also navigate to the shoulder of the road. Took the car to the dealership where they confirmed P111A engine overheated DTC and coolant leak. CX-9 has a cracked cylinder head, the exact problem outlined in Mazda TSB 01-013/21. This happened at 61,xxx miles...roughly 1,000 miles outside the powertrain warranty however it's highly likely this crack and leak developed well before the end of the powertrain warranty period.
Official recalls
221V875000 · Fuel System, Gasoline:delivery:fuel Pump
Nov 12, 2021
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 inside the low-pressure fuel pump may crack and deform, potentially causing the fuel pump to fail.
Consequence & remedy
Consequence: Fuel pump failure may cause an engine stall, increasing the risk of a crash.
Remedy: Dealers will replace the fuel pumps, free of charge. Owner notification letters were mailed July 18, 2022. Owners may contact Mazda customer service at 1-800-222-5500 Option 4. Mazda's number for this recall is 5321K.
19V403000 · Electrical System:wiring
May 30, 2019
Mazda North American Operations (Mazda) is recalling certain 2018 CX-9 vehicles. The wiring harness may disrupt electrical communications and disable the passenger frontal air bag, turn signals, and/or engine starting system.
Consequence & remedy
Consequence: The passenger frontal air bag may not deploy, increasing the risk of injury. Inoperable turn signals prevent the driver from signaling to other drivers, increasing the risk of crash.
Remedy: Mazda will notify owners, and dealers will repair the wiring harnesses, free of charge. The recall began July 26, 2019. Owners may contact Mazda customer service at 1-800-222-5500, Option 4. Mazda's number for this recall is 3419E.
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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