2018 Mazda CX-5: engine overheating

Filed Oct 28, 2026 · Engine · WA

My 2018 Mazda CX-5 Touring (2.5L non-turbo engine with cylinder deactivation) developed a burning oil smell that steadily worsened over several days. On XXX, at about 61,300 miles, I saw smoke coming from the engine compartment after driving. The engine had not overheated, and the car was regularly maintained. On XXX, an independent repair shop (A&M Auto Repair, [XXX] a large active oil leak. After steam cleaning the engine and removing the exhaust manifold, they found engine oil leaking from a hairline crack in the cylinder head, directly onto the hot exhaust manifold. The engine was also about one quart low on oil. The shop recommended replacing the cylinder head assembly, at a cost of about $5,700 before tax. Oil leaking onto the exhaust manifold is a fire hazard, and the smoke could reduce visibility for other drivers. Many other owners of 2018–2020 CX-5s with this engine have reported the same cracked cylinder head failure. I contacted Mazda Customer Experience (case number XXX) to request assistance. Mazda declined because the repair was diagnosed and performed by an independent shop rather than a Mazda dealer. I'm submitting this complaint so the federal safety agency can evaluate whether this cylinder head failure is a safety defect that warrants a recall. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

Filed Jul 1, 2026 · Transmission · CA

My Mazda 2018, CX-5, Grand Touring, was diagnosed with a cracked cylinder head at 64,599 miles. This issue could posed a safety hazard for not only us but others on the road by: *Engine Failure / Sudden Loss of Power-A crack allows coolant and oil to mix or leak, leading to overheating and potential catastrophic engine seizure. A seized engine can cause sudden, unexpected loss of power — especially dangerous at highway speeds or during lane changes/merges. *Oil and Coolant on the Road-Leaking fluids drip onto the roadway, creating slick surfaces for motorcyclists and other vehicles — similar to a spilled oil hazard. This is especially dangerous on curves and in wet conditions. *White Smoke / Steam Billowing from Exhaust-When coolant enters the combustion chamber, it burns off as thick white smoke. This can instantly reduce visibility for drivers behind the vehicle, potentially causing rear-end collisions. *Fire Risk-If oil leaks onto hot exhaust manifolds or engine components, it can ignite. An engine fire can spread quickly and, in traffic, puts surrounding vehicles and occupants at risk. *Debris from Engine Destruction-In extreme cases, a severely overheated or seized engine can cause internal components to fail violently. Debris from a catastrophic engine failure can damage undercarriages of nearby vehicles or become road hazards. *Stalling in High-Risk Locations-A vehicle that stalls due to engine failure in a tunnel, on a freeway on-ramp, in an intersection, or on a bridge creates an immediate collision risk for surrounding traffic. This is part of why Mazda's handling of the cylinder head defect is so problematic — it's not merely a costly repair, it's a public safety issue that arguably warrants regulatory attention (the federal safety agency). We had NO warning lights, no overheating issues. Repairs have been made to the cost of almost $5400.00 *Please note there are many, many people complaining of this same issue on this model of car in multiple on-line forums.

Filed Mar 30, 2026 · Engine · CT

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

Filed Apr 24, 2024 · Transmission · MA

Cracked cylinder head. Burning oil smell. Coolant leaking into oil. Car purchased a year ago for $21,500. Dealer I bought it from paid 1/2 after sending it out to Mazda to be diagnosed and fixed.

Filed Apr 12, 2024 · Engine, Transmission · VA

Noticed a burning oil smell coming from the car along with leaking oil in the driveway. Vehicle has 53000 miles on it and was 3 months out of powertrain warranty but still under the 60000 mileage cap. Local Mazda dealership came back saying that it was a "SA-037/23 Oil leak at cylinder head, cylinder head replacement with parts kit" and quoted $5100 to repair. Dealership stated that the vehicle was unsafe to operate. There were no dash indicator lights or symptoms of overheating to indicate that there was a problem outside of the smell. After the diagnosis was made, we researched and found that this was a commonly reported problem for this model year

Filed Apr 3, 2024 · Engine · OK

Oil started to leak along with a burning smell, ended up being a cracked cylinder head at 77k miles. It was not in an accident & it did not overheat. But it appears this is a known issue with this make, model & year. Now Mazda only wants to pay $1k of $5k charge. I bought the dealers extended warranty, up to 75k miles, which apparently means nothing. My next car will not be Mazda.

Filed Dec 29, 2022 · Engine · MA

On 12/23 I was driving on the highway approaching exit 43 A-B on I-95 N and the engine oil light came on, I started monitoring the temperature of the car and it was holding steady, neither was it dropping nor was it overheating. I continued driving for a minute more, I am half mile away from home at this point and I smelled burning oil. I pulled the car over and opened up the hood, I turned on the flashlight on my phone and I could see oil on the engine floor. I called up Mazda dealership near me and they were closed for the holidays so I left voicemails. After a couple of days of no answers, I was able to get through to someone and they said they'll take the car in however they can't guarantee if they will be able to even look at it until after the holiday, I speak to the service manager and mention that I have an upcoming trip out of state for Christmas, they said they did not have any loaner cars available either. I got my car towed to the dealership anyways. Next day I get a phonecall from them stating that the oil pump and pressure was fine and they suspect it was the engine head that was causing the leak and that it would cost me 6000$ to fix it. Along with that I need to get my belt tensioner fixed which would be around 680$. The car's estimated value is about 12000$ and I am being asked to pay more than half its value after owning it for 4 years to fix something that was caused by wear and tear. I also did a little digging and I've found that my car falls under ones that have been identified by Mazda to probably have a defective engine head. I am attaching the reports that I have discovered in my research with this submission. I am imploring for assistance in this matter as I cannot afford this expense and I would not like to part ways with something that has been reliable for the last 4+ years. Dealership- Wellesley Mazda

Filed Aug 24, 2018 · Electrical · 6,000 miles · MD

On two separate occasions in the last month, during key on/startup/initialization, I will get an adaptive cruise control/aeb/lane keeping system failure. This is due to a fault in the camera module. Adaptive cruise control still works above 20 MPH indicating that the failure is in the camera module. Failure is latched for the key cycle and but will recover after a long key cycle. 1st time the failure set, it was very warm out so I believed this was due to an overheat. The second time the failure set the temperature was in a normal range so my hypothesis is wrong. No unusual situation is occurring at startup except the failure. Have not taken to the dealer yet.