What 113 owners told NHTSA about the 2018 Mazda Cx-50

I am reporting a safety issue involving engine failure and fumes entering the vehicle cabin as well as unintended braking post major engine repair at 75,000 miles on my 2018 Mazda CX5. My vehicle developed engine problems consistent with a cylinder head/coolant defect and began allowing fumes/smoke to enter the cabin while driving. This created a health and safety concern for occupants. I reported this to the dealership and was told the vehicle was safe to drive despite the presence of fumes in the cabin. A major engine repair was later performed. A few days following the repair, additional warning lights and system malfunctions appeared, including brake system warnings, and the vehicle later braked unexpectedly while driving nearly causing me to be rear-ended. The vehicle has been inspected by the dealership, but the root cause of the fumes and subsequent safety issues has not been clearly explained. This situation created a safety risk due to exposure to fumes inside the cabin and unexpected vehicle behavior while driving. Smoke/fumes video and any additional documentation can be provided upon request. Attaching the costly invoice as well.

NHTSA ODI 11730227

My 2018 Mazda CX-5 with 81,000 miles and an up to date maintenance record started leaking oil after an oil change. It started to notice smoke coming from under the hood and a puddle of oil in my garage floor. I took it to the shop where they determined it was a cracked cylinder head. I purchased this vehicle new from the dealership, and I have taken really good care of it. They need to issue a recall because it is a very expensive repair. Shame on you Mazda!!

NHTSA ODI 11728174

Vehicle Information Year/Make/Model: 2018 Mazda CX-5 Engine: 2.5L Mileage at Failure: Approximately 115,000 miles Component: Engine Complaint Summary: I am reporting a sudden and unsafe engine failure involving a cracked cylinder head in my 2018 Mazda CX-5. This failure occurred without warning at approximately 115,000 miles and resulted in significant oil leakage from the engine. Description of the Failure and Safety Risk: While operating the vehicle, I detected a strong burning oil odor followed by visible smoke coming from the engine compartment. Upon inspection, it was determined that the cylinder head had cracked, allowing engine oil to leak onto hot engine and exhaust components. This condition presents a serious safety hazard, including the risk of fire due to oil contacting high-temperature surfaces. Notably, there were no warning lights, messages, or prior indicators of any issue before the failure occurred. The vehicle has been properly maintained and has not experienced overheating or misuse that would reasonably lead to this type of failure. Repair Information: The vehicle was diagnosed by an authorized Mazda dealership, which confirmed a cracked cylinder head. The estimated cost of repair is approximately $5,130. Additional Information / Defect Pattern: Through independent research, I have identified multiple reports of similar failures involving Mazda 2.5L engines in comparable vehicles. These reports describe nearly identical symptoms, including sudden oil leakage, smoke, and cracked cylinder heads at relatively low mileage. This pattern suggests a potential manufacturing or material defect rather than normal wear and tear. Manufacturer Response: I have contacted Mazda Customer Experience and escalated the matter. Mazda has declined to provide any assistance, citing the vehicle being out of warranty, despite the nature of the failure and associated safety concerns. Summary: This issue involves a critical engine component failure that can le

NHTSA ODI 11727886

My 2018 Mazda CX-5 AWD (2.5L SKYACTIV-G, non-turbo) was diagnosed by a Mazda dealer with a cracked/leaking cylinder head, a known manufacturing defect in the casting of the aluminum cylinder head. Engine oil is leaking from the rear of the cylinder head onto the exhaust manifold, creating a burning oil smell and visible oil accumulation at the rear of the engine. This is a documented fire hazard. The Mazda dealer confirmed the diagnosis matches Technical Service Bulletin SA-031-21, which Mazda issued in May 2021 specifically for this defective cylinder head design on 2018–2019 CX-5 models. The dealer additionally informed me that Mazda has internally acknowledged this as a growing, widespread problem across the 2018–2021 CX-5 model years, and that a recall may be forthcoming. Mazda customer service denied my goodwill repair claim despite acknowledging the TSB. The estimated repair cost is $7,000. The vehicle is currently not being driven due to the fire risk of oil contacting the exhaust manifold. This defect appears to affect a significant number of 2018–2021 Mazda CX-5 vehicles. I am requesting NHTSA open a formal safety defect investigation and compel Mazda to issue a recall. Multiple other owners have reported the same issue on NHTSA and in owner forums. This is a manufacturing defect not normal wear and tear and poses a serious fire safety risk to consumers.

NHTSA ODI 11725144

Vehicle developed burning oil smell. Dealership diagnosed a cracked cylinder head. No warning lights (yet. Eventually low oil pressure light would come on.) Potential for engine to lock up and lose power while driving putting occupants and others at risk. Know problem for 2018-2021 model years. Car no longer under warranty. Cost to repair 7,100. Technical Service Bulletin SA-031-21 issued regarding this problem.

NHTSA ODI 11722666

2018 Mazda CX-5, 58,182 miles. Report date is 3/7/2026, low mileage for it's age. Vehicle has been exclusively purchased and serviced at the same authorized Mazda dealership for the lifetime of the vehicle, with all maintenance records on file. I began experiencing a strong burning oil smell inside the passenger cabin while driving. The fumes were noticeable to both the driver and passengers, creating a potential carbon monoxide/combustion fume exposure hazard that posed a safety risk to all occupants. Upon bringing the vehicle to the dealership, the technician diagnosed a cracked cylinder head requiring full replacement. This is a significant structural engine defect. Despite the vehicle being dealer-serviced its entire life, the repair cost was initially placed entirely on the owner. Mazda eventually provided partial financial consideration, though the root cause of why a cylinder head cracked on a well-maintained 58,182-mile vehicle was never adequately explained. I am filing this complaint because fumes entering the passenger cabin represent a serious safety defect, and I believe this issue may affect other 2018 CX-5 owners.

NHTSA ODI 11722750

Cracked cylinder head confirmed by Mazda Dealership. No warning lights or indicators. We noticed white smoke and a burnt plastic smell after a drive one night. Dealership confirmed oil was leaking onto the exhaust, a potential fire hazard.

NHTSA ODI 11722628

All of a sudden, my engine started making this ticking noise. I brought it to a mechanic, and he said the noise is coming from inside the engine. He checked for codes and everything, but nothing came up. The only way to look at it is to take the engine apart from what he told me. I started researching for solutions online before doing this and I came across other Mazda CX5 owners complaining of the same thing. I listened to a few of these videos of the sound it makes and sounds just like my car. Apparently, it is a common issue connected with the Hydraulic Lash Adjusters, and I am amazed that Mazda has not reached out to people affected by this. I am not sure what the long-term issue is with this noise, but it can't be good if it's in the engine. Who knows what kind of damage it could cause.

NHTSA ODI 11719213

Noticed the smell of burning oil and smoke from the engine while driving on the interstate with my husband and young children in the vehicle. Pulled over at a gas station to inspect and discovered large amounts of oil leaking. While at the gas station the low oil indicator came on. There were no warning or check engine lights prior to the incident. The dealership diagnosed cracked cylinder head. This was an extensive and costly repair. I have now learned that Mazda is aware of how common this issue is with this year/make/model. This should be a covered repair or recalled part.

NHTSA ODI 11718745

Turned car on when leaving for work. Smelled a strong burning smell. Fluid all under car on the driveway. Took the vehicle to repair shop and they stated that it was the cylinder head and that there was a possible recall or warranty extension for this particular issue. I called Mazda and they said it was an issue but for the 2019 model and not the 2018. After doing some research I have read where this issue seems to be happening for the 2018 as well and they are not taking responsibility for it.

NHTSA ODI 11716158

While driving, my 2018 Mazda CX-5 experienced a sudden and complete loss of engine power without warning. The engine shut down while the vehicle was in motion; however, electrical systems such as the radio, heat, and electronics remained operational. The vehicle lost propulsion, creating a serious safety risk in traffic. The vehicle had recently been serviced at an authorized Mazda dealer for completion of PCM and fuel-system recalls. Shortly after recall service, the engine failure occurred. No warning lights or prior symptoms were present. An independent mechanic suggested possible engine seizure, but a full diagnostic evaluation (including compression testing or internal inspection) has not been completed. The cause of the sudden power loss remains undetermined. This incident represents a potential safety defect involving unexpected engine shutdown and loss of propulsion.

NHTSA ODI 11714123

The infotainment system consistently changes stations and volume on its own. Knob will not allow you to make adjustments . Contacted dealer and infotainment Is not covered under warranty , or extended warranty. Now the collision notification is not working. Warnings from system that it has failed and causes system to not Register any movement . This has been going on recently. Now have to drive it as it doesn’t have the system. And have to use my Apple play for radio as infotainment keeps failing to include radio and navigation Told by dealer that the infotainment system is not Mounted into the dash and sticks up , so the heat from sun and summer has fried th system. Has been ongoing for over a year just found site to report it . Will not buy another vehicle with infotainment system sticking up out of dashboard

NHTSA ODI 11708847

Cracked cylinder head due to defect in the casting process. Oil leaking thru the crack landing on the exhaust manifold causing an odor and possibly toxic fumes in the cabin of the vehicle.

NHTSA ODI 11707998

Mazda has inspected the car and determined that there is a crack in the cylinder head. This is apparently a known defect in 2018-2021 Mazdas with 2.5L engines, including, without limitation, the 2018 Mazda CX-5. The cracked cylinder head has caused leaking coolant, which can drain into the engine and create serious safety issues. Mazda is aware of the issue, however, they are claiming that it is not covered by warranty.

NHTSA ODI 11705314

Hydraulic lifters keep having issues

NHTSA ODI 11699908

The contact owns a 2018 Mazda CX-5. The contact stated that while driving at 45 MPH, there was smoke coming from the engine, and the contact smelled an oil-burning odor. No warning lights were illuminated. A dealer was contacted. The vehicle was towed to the dealer where it was diagnosed and determined that the cylinder head was damaged, causing oil to leak into the cylinders, and that the engine needed to be replaced. The manufacturer was notified of the failure, and promised to open a case and give the contact a callback within 24 to 48 hours. The approximate failure mileage was 59,000.

NHTSA ODI 11694487

Driving fine at low speeds (under 40mph), once I accelerate to highway speeds the engine misfires, check engine light flashes, Smart City Brake System Malfunction, Radar Malfunction, and car losses all engine power. Car just coast, lights and brakes still work. Check engine code moves around and will be on cylinder 3 sometimes and cylinder 4 other times. Able to replicate this issue multiple times. Serious safety concern.

NHTSA ODI 11693210

2018 Mazda CX-5, 2.5L Naturally Aspirated Engine The vehicle has been diagnosed with a leak from the cylinder head cover, resulting in engine oil dripping directly onto the exhaust manifold. This issue causes noticeable smoke and a strong burning oil odor inside the cabin while the engine is running. This defect presents multiple serious safety concerns: 1) Health hazard due to prolonged exposure to burning oil fumes inside the vehicle. 2) Fire risk from oil contacting hot engine components. 3) Potential engine failure, which could lead to vehicle stalling or loss of control, increasing the risk of a crash and possible loss of life. Mazda issued Technical Service Bulletin TSB #SA-031-21, which introduced a redesigned cylinder head for 2018–2019 CX-5 models. The release of this TSB indicates Mazda’s awareness of the underlying design flaw. There is substantial evidence, including numerous owner reports, that this is a widespread issue affecting these model years. The defect is not related to vehicle mileage or user negligence. Mazda should be held fully accountable and take corrective action by issuing a formal safety recall or offering an extended warranty to affected owners. Immediate attention to this matter is necessary to protect consumer safety and prevent future incidents.

NHTSA ODI 11691786

Cracked cylinder head leaks oil directly onto hot exhaust, causing smoke, fumes in cabin and a fire risk.

NHTSA ODI 11689793

the cylinder head has a crack in it witch sprays oil all over the engine.it also sprays oil on to the very catalitic converter that's very hot .smoke is everywhere and iam afraid it will cause a fire

NHTSA ODI 11685332

I own a 2018 Mazda CX-5. I currently have 64,770 miles on the car. I have had a burning smell and smoke coming from the engine. The car was taken to the dealer (John Kennedy Mazda Conshohocken) and I was told it was fixed by replacing a gasket. The smell and smoke persisted. I took it back to the dealer and now I am told there is a leaking cylinder head. I do not feel safe driving this car especially with my kids in the car while the engine is smoking. I have had to pull over on the highway due to this. No warning lights were on until a week prior to taking it back a second time when my oil light finally came on.

NHTSA ODI 11685038

Back up cameras fail infotainment system reboots and maps on the system inadvertently counts stops plus changes volume at loudspeaker telling me “this is the level “ and is on highest volume. Which you can’t turn down. All are dangerously interfering with driving. Please put pressure on Mazda to fix and not just update software when the problem has been fixed called CMU

NHTSA ODI 11685123

Engine Cylinder heads started to leak at 75k miles causing oil and coolant to leak and puddle. This was after a fuel pump recall.

NHTSA ODI 11680493

Had an oil leak suddenly appear on the vehicle with only 55400 miles. Found there are technical service bulletins for this motor that the head cracks causing leaks. It is on many forums. Reached out to Mazda and got zero help

NHTSA ODI 11659102

2018 Mazda CX5 2.5 ltr engine. Major oil leak that has been diagnosed as cracked or porous aluminum casting on the cylinder block. Oil is dripping consistently out of the problem area onto the manifold, causing smoke to flow into the cabin of the car and out of the hood as well. Car is currently at a Mazda dealership for a second diagnosis that confirmed the leak. Car is 3,000 miles out of warranty. Waiting to hear what the dealership is going to do. I also have contacted Mazda corp. and have a case# to take further action if needed. As you can see by the list of "engine" complaints for this problem, it is well documented that this is not an isolated issue.

NHTSA ODI 11656944