9.1

really awful
Crashes / Fires:
0 / 0
Injuries / Deaths:
0 / 0
Average Mileage:
1,984 miles

About These NHTSA Complaints:

The NHTSA is the US gov't agency tasked with vehicle safety. Complaints can be spread across multiple & redundant categories, & are not organized by problem. See the Back button — blue bar at the very top of the page — to explore more.

Get notified about new defects, investigations, recalls & lawsuits for the 2018 Mazda CX-9:

Unsubscribe any time. We don't sell/share your email.

Get free help with your lemon!
close ad
problem #45

Aug 302023

CX-9

  • miles
Engine coolant leaks at cylinder heads I started noticing the problem at around 50000 miles its a small coolant leak but car is almost 6 years old and now 54000 miles

- Belvidere, IL, USA

problem #44

Jan 202024

CX-9

  • miles
I recently bought a Mazda CX-9 and noticed that my vehicle was slightly overheating. The coolant level was very low. I took it back to the dealership I bought it from and they confirmed that there was a crack in the cylinder head and are working on the repair. After further research, I am seeing this is common with these models. Mazda is aware but not taking responsibility.

- Austin, TX, USA

problem #43

Jan 192024

CX-9

  • miles
Cracked Cylinder Head Verified by Mazda Dealer. Noted it seems to be a very common problem with Mazda cx9 2018 models and has Multiple TSB on issue so I kept very close eye on car and took it in as soon as I smelled burning smell suggesting a leak, before the car had the chance to overheat and put myself and kids in danger. My car is under 40k miles for a 2018 with consistent maintenance - this is known problem since 2021 and needs to result in a recall.

- Clarks Summit, NY, USA

problem #42

Jan 122024

CX-9

  • miles
Mazda has a known technical service bulletin [XXX] which has numerous engine cylinder heads which leaks coolant causing the engine to overheat without warning. On new cars. Mazda knows it-??s an issue and has not pushed this information down to its consumers. [XXX] INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

- Alexandria, VA, USA

problem #41

Dec 212023

CX-9

  • miles
Engine coolant leaking due to cracked cylinder head, found by Mazda dealership service inspection and diagnostics. Powertrain warranty only covers this until 80,000 miles, our vehicle is 116,000.

- Geneva, IL, USA

problem #40

Dec 152023

CX-9

  • miles
At 102,000 miles I have a cracked cylinder head

- Chilton, WI, USA

problem #39

Dec 052023

CX-9

  • miles
Cracked cylinder head resulting in no heat, leaking coolant and risk of overheating and fire. Crack on backside of cylinder head near exhaust manifold bolts. Weight of exhaust manifold is too much for the cylinder head and results in a Crack around the bolt. Cylinder head was casted too thin at the factory resulting in the head no being able to support the weight of the turbo and exhaust manifold. Mazda is not covering the defect under goodwill when customer is outside of warranty even though it effects every 2.5 turbo engine made between 2015 and 2020.

- Helmetta, NJ, USA

problem #38

Jan 192023

CX-9

  • 68,000 miles
The contact owns a 2018 Mazda CX-9. The contact stated that while the vehicle was parked, he observed condensation under the vehicle. The vehicle was towed to an independent mechanic where it was diagnosed that the engine needed to be replaced. The vehicle was repaired but the failure persisted. The contact stated that while the vehicle was parked, he observed condensation under the engine compartment and on the top of the engine. The vehicle was taken to an independent mechanic where it was diagnosed that there was a crack in the cylinder head and that the engine needed to be replaced. The vehicle was not repaired. The manufacturer was notified of the failure. The failure mileage was 68,000.

- Hollywood, FL, USA

problem #37

Nov 062023

CX-9

  • miles
My 2018 Mazda CX-9 developed a rapid overheating issue which was determined to be caused by a cracked cylinder head. This was a known issue by Mazda as noted in a technical service bulletin (Mazda TSB 01-013/21). I've been told by Mazda corporate and the Mazda dealership where the car is currently parked that this bulletin means nothing and will they will not cover the cost of repair. My extended warranty is also telling me that they will not cover the cost of repair because they don't cover damage caused by overheating. Even though The leak caused the overheating in the first place.

- Claymont, DE, USA

problem #36

Oct 012023

CX-9

  • miles
Coolant leak in the 3rd cylinder, causing the car to overheat and cracking cylinder head, making inoperable.

- Asheville , NC, USA

problem #35

Oct 162023

CX-9

  • miles
We noticed a coolant leak and took vehicle in for service. Told that engine has a Coolant Leak at Cylinder Head TSB 01-002/23. 5 year old vehicle, 56k miles. No other warnings. All maintenance has been previously performed as required.

- Bend, OR, USA

problem #34

Oct 092023

CX-9

  • miles
As I was driving 26 mile trip to work I noticed a red light illuminated on dash indicating the temp was about 240-260. I pulled into the parking lot immediately turned car off. After work (8 hour shift) drove home temp stayed at 200-210. The next morning I took it to the mechanic I-??ve used for years. He did a visual detailed inspection finding that the water or antifreeze in the radiator was low. The antifreeze in the over flow tank was about an inch or so above the -??L-?? line. He said there may have been an air pocket in it, a leak, water pump or thermostat going out. Watch the fluid levels daily, if the lower again take it to the dealership where I purchased it (4 months ago with 106K miles on it). I do have a 3 year or 30,000 mile warranty through the dealership. 4 days later I was very observant watching the temperature gauge. It went up to 240 briefly, so I got home and had my ex-husband check it. Both the radiator and the overflow tank were bone dry. Topped off radiator with antifreeze and the overflow tank to the -??F-?? line. Car had cooled and right before topping fluid started. There is no noticeable sign of a leak (smell, white smoke from exhaust, visible puddles of anything on the motor or the ground where I-??ve parked. Today is Thursday 10/12 and I can-??t get an appointment with dealership until Tuesday. I-??ve been reading a lot online about this being a very repetitive issue. In some cases new engine replacement required. Mazda is well aware of not a few but NUMEROUS issues and complaints, a recall is needed for this situation. Right is right and fair is fair!!

- Ellisville , MS, USA

problem #33

Oct 092023

CX-9

  • miles
Went in to the mechanic to get a regular oil change and noticed a liquid slushing sound after starting the car up. Was informed that there is a major coolant leak somewhere in the car. Took it to Mazda dealership right away who confirmed that it is a cracked cylinder head. I got lucky that the car did not overheat on the road and happened to catch it in the nick of time. No check engine lights or low coolant lights came on at all.

- Houston, TX, USA

problem #32

Sep 292023

CX-9

  • miles
Coolant leak not from radiator but from the engine

- Pittsburg, CA, USA

problem #31

Sep 032023

CX-9

  • miles
Car started idling rough and losing power at 135000 miles. Then started to overheat. Mechanic noticed coolant was low and added some. Problem continued to get worse and now engine won-??t turn over. Mechanic said it was a cracked head leaking coolant into engine and it-??s a known problem with the CX-9.

- Houston, TX, USA

problem #30

Sep 182023

CX-9

  • miles
Just noticed coolant leak during oil change. Vehicle has 77,000 miles. Power train warranty is only to 60K. The vehicle is undriveable without major engine work or engine replacement.

- San Jose, CA, USA

problem #29

Aug 302023

CX-9

  • miles
The cylinder head cracked and leaked engine coolant at 72K miles. This is a known design flaw IAW TSB 01-007/22. Vehicle overheated.

- Mount Dora, FL, USA

problem #28

Aug 262023

CX-9

  • miles
Coolant leak from casting defect. Common issue.

- Litchfield , ME, USA

problem #27

Jun 012023

CX-9

  • miles
I noticed my 2018 mazda cx9 Sweet smell coming out of the engine.. When we were driving, a memo came up on my car screen and says please turn off vehicle as soon as possible, overheating. I was Scared That my car could have stopped in the middle of the freeway with my kids in it. My current was low. My engine was really hot and so we took it in to Mazda dealer. They diagnosed my car, and they said it had a cracked cylinder head by the exhaust manifold and because of that, it overheated my engine. This is a manufacturer problem. And it could have harmed my family. Mazda now doesn't wants to help me fix my this car, even when admitting they are fully aware of it. This happening on a freeway would have caused a major accident. There are Technical service bulletin on this case but people are Still in danger.

- Pearl City, HI, USA

problem #26

Aug 072023

CX-9

  • miles
The vehicle started leaking coolant, I had it towed to dealer to prevent further damage. They said it has a cracked head, which is a known issue with the 2016-2019 Mazda's, and is acknowledged by Mazda to be their fault. They have posted on a service bulletin that it was caused by added stress during manufacturing. Like many others, they want me to pay over 8k dollars for the repair. This is ridiculous as Mazda has stated that it is their fault.

- Commerce, MI, USA

Read the next 20 complaints »