What 125 owners told NHTSA about the 2018 Mazda Cx-90 Phev

A known faulty cylinder head in these cars is breaking. A simple search of the web shows numerous owners have had the same problem. Mazda dealers KNOW it is a problem. They have upgraded the part, but it comes at a cost of approximately $7800 to owners of said vehicles.

NHTSA ODI 11523363

Engine cylinder head cracks open due to bad design where turbo puts too much weight and vibration resukting in coolant leaking out of engine. Mazda has a bulletin out for this issue and I took it to a Mazda dealer for repair. They confirmed this was the issue.

NHTSA ODI 11522720

Sorry there was no incident

NHTSA ODI 11521825

Bought car new in 2018. At 72,600 observed coolant leaking from backside of motor. Carried to Classic Mazda of Texarkana,TX for diagnostic test. Has a cracked cylinder head.Mazda refused to pay to fix or assume any responsibility for the design flaw. Turbo charger is too close to the cylinder head causing heat issues over time resulting in cracked head/coolant leak.

NHTSA ODI 11521555

Coolant leak at cylinder head. It is available for inspection. Driving on the highway and the car overheating light came on. Yes it has been reproduced and diagnosed as part of the TSB 01-013/21. No warnings, no notice of leaks before this happened. Noticed this in January - and thought it was just a one off and had the coolant topped off. Nothing happened until a month later that is when I took it to the mazda dealer. Safety issue as no one knows about it until their light comes on and they take it to the dealer to look at. Having this happen in the middle of nowhere on a highway with three small kids is a nightmare. This issue needs to be investigated. It is definitely a safety issue. It is shocking to know that Mazda has known about this for a couple years now based on the date of the TSB. A letter, at the very least, should have been sent out to all owners. Instead they let us all sit with a ticking time bomb that will be cost prohibitive to fix.

NHTSA ODI 11515906

The vehicle has a cracked cylinder head as a result of stress put on the block from a bad exhaust manifold design. This is a known issue to Mazda and service bulletin was sent out to all their dealerships in 2021. Mazda only offered to pay a very small portion of the repair and puts the rest of the cost on the customer. Luckily I caught the issue early but this could have been dangerous if the car overheated and the engine failed on the highway. There are countless other stories of consumers having the same issue with the CX-9 and CX-5 of the same year. Many resulting in engine failure.

NHTSA ODI 11515492

Infotainment screen has spider cracking from faulty screen when manufactured. Open TSB stating this and Mazda refuses to replace under warranty after 5 months of owning vehicle, spider cracks got worse this year. When i got more spider cracks i contacted mazda support since the first time I contacted a local dealer. Mazda support denied replacement because “ i do not get my car serviced through mazda”, this screen issue has nothing to do with a car being serviced. This is a safety issue as you can not see parts of the screen and will only get worse and make the whole screen inoperable when using navigation.

NHTSA ODI 11514555

I own a 2018 Mazda CX – 9 with only 53,300 miles. I noticed something was wrong with my engine and had no idea what the issue was. My car would not shut off immediately when I turned it off and the fan was on super high speed. The day before my appointment with my mechanic, the engine light turned on. I was stuck in a parking lot and a friend suggested I use his car to go buy coolant just in case it was needed. Sure enough, I was completely out of coolant. When my mechanic inspected the car he told me I had a coolant leak and suggested I take it to the dealer as they would know immediately what the problem was. I started researching to see if this was a defect and sure enough, Mazda has been aware of the defect with the cylinder head (TSB) not supporting the turbo of the engine causing it to crack and mix with the engine oil in various models for years, yet continue to sell cars with this known defect. I understand that it may not be life threatening yet! But it could have been should my engine had blown while I was on the freeway causing a horrific accident. How are they allowed to continue manufacturing and sell cars with a known issue for years and not even be reuqired to make a recall to have the part replaced with a stronger one? This is issue is happening to 100's of customers worldwide. This is something that should be investigated.

NHTSA ODI 11514604

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.

NHTSA ODI 11511374

The infotainment system screen has developed several cracks in the upper left-hand corner of the screen. Often time these cracks look like spiderwebs or frost --it's commonly referred to as "spider cracking." This is the second time my vehicle has had this issue. At the present time, the cracks are contained to the upper left-hand corner of the screen, but they are getting larger. The vehicle has been inspected by my local MAZDA dealership and I'm awaiting a resolution. As I understand, this is a known issue with 2016-2017 model years and a TSB has been issued for these years. MAZDA should extend the TSB to 2018 and beyond.

NHTSA ODI 11510436

The main infotainment display randomly exhibited "spider cracking" which obstructs the view of the material being displayed within the screen. It is unsafe because the operator is unable to see maps, time, locations, controls, reverse cameras, etc. All of these are displayed in the screen and, due to the manufacturing defect, the operator is distracted by straining to see what is displayed behind the cracking. This is a well documented issue plaguing Mazda vehicles. Mazda has admitted it as defective, and are fixing the problem in the 2016-17 models. However, the 2018 model (which has the same screen as the 2016-17) is being refused. The fix needs to be extended to the 2018 model and beyond since it iw clear this it is still a widespread issue. It is well documented that once the cracking starts, it quickly spreads to the entire screen if not repaired, causing even more danger to the operator who will be distracted while attempting to see the display behind the screen.

NHTSA ODI 11508426

This weekend Mazda CX-9 started leaking coolant from the firewall side.

NHTSA ODI 11507063

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.

NHTSA ODI 11501873

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.

NHTSA ODI 11499063

I was resting my foot on my brake in the middle of sealed traffic and when I eased up to move forward when traffic my brakes did stop causing me to bump the car ahead of me. After that what came next was that my car then accelerated forward with my foot still on the brake. By then 2 other vehicles were involved in this accident. My car is now totaled from this.

NHTSA ODI 11497382

I keep getting a automatic emergency braking malfunction alert

NHTSA ODI 11496403

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.

NHTSA ODI 11490188

After sitting in the heat of summer, cracks appeared on two of the corners of the LCD navigation screen making it very hard to see portions of the screen.

NHTSA ODI 11490208

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.

NHTSA ODI 11490050

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.

NHTSA ODI 11489489

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

NHTSA ODI 11488281

> I have a 2018 Mazda CX-9 with about 70,000 miles on it. Since 2020 this vehicle started developing cracks in the infotainment center screen. I only had about 23,000 miles on it at that time. the cracks are now starting to obscure my back up camera, communication system and nav system displays causing a safety issue. It is distracting to not be able to see clearly on this screen and I am afraid something will happen to me or my kids. About a year ago I did take this car to the local mazda dealer, for the longest time I thought I did something to it, but I did not. They called mazda customer service and no good will was offered. there is a technical service bulletin out but not a recall. There are several models older than my vehicle that have had this screen repaired free of charge by mazda. Same issue - nothing different then what is going on with my car. There are many many of the very same complaints online. can some please investigate this issue. it is ridiculous.

NHTSA ODI 11484377

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.

NHTSA ODI 11482726

Mazda has refused to admit and repair a clearly defective screen, affecting visibility of the camera system, navigation, climate controls and infotainment. Pictures attached are several months old and the issue continues to get worse. The dealer says "corporate won't cover it", corporate customer service will not respond to repeated attempts at contact other than a generic "your VIN is not covered". Service alert direct from Mazda and pictures of my screen showing the EXACT issue are attached. For a $40k+ vehicle with less than 30k miles on it (less than 20k when the issue started), this is unacceptable. Please hold Mazda accountable.

NHTSA ODI 11481586

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.

NHTSA ODI 11481366