2018 Mazda CX-5

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 (NHTSA). 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.

2018 Mazda CX-5 AWD with 2.5 L engine, non turbo. Car has 98,914 miles. Rear differential started leaking oil. Dealer stated that the differential needs to be replaced, for $5,003.33. Manual does not provide for oil change intervals. Lifetime oil. 98K must be the life expectancy. Has not been fixed yet. Sitting in the garage dripping oil onto a piece of cardboard. independent shop looking for a low mileage used differential.

Like many other complaints. My 2018 Mazda cx5 GT is having the same issue with the cracked cylinder head. I only have about 36-38k mileage on it ( I forgot the exact). Mazda dealership will not cover the cost. NEVER had an accident to the front and only one accident to the back when I got rear ended in 2019. If this is a wide spread issue, why is this not a recall? and why is it only the turbo engine gets extended warranty? The repair cost right now approximately $9,500. I never do any maintenance at Mazda so I doubt they will give me the good will assistance but I am still waiting for an answer. I hope NHSTA will do something because this issue will continue with all other owners that have the same year model.

My 2018 CX5 just hit 50,000 miles recently and I smelled something burning and saw smoke coming from the hood while I was stopped for a school bus. I immediately stopped driving due to fire concerns. The vehicle has a cracked cylinder which is a known issue for this vehicle. Mazda has no plans to correct this issue other than issuing a technical bulletin. I feel that Mazda should repair this at their cost because it is a defect and the vehicle only has 50,000 miles. Instead I have to pay nearly $5,000. This is hard to believe! Transcript from dealer: The technician reported an oil leak from the cylinder head, specifically indicating a crack in the number four lifter valley that is causing fluid to leak down the engine block. This issue is recognized as a known problem, and the technician will check if it is covered under warranty. Repairing the cylinder head will require significant labor, including dropping the engine, and will take some time to complete. Services being performed: - Oil change. - Inspection for oil leak issue. Recommendations: - Replacement of the cylinder head due to the identified oil leak. Multi Point Inspection $4870.22

Upon acceleration it’s not shifting gears properly. The rpm’s rev but the vehicle doesn’t go faster. Traffic behind me continued to accelerate to where i was concerned about being rear ended. I Have not taken it to anyone yet..it has done this a couple of times. Even though it’s a 2018 it only has 25000 miles on it. The dealer is an hour away and i”m afraid to drive it there because i don’t want to cause more problems. No warnings lights or messages.

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.

2018 Mazda CX-5, 2.5L NA Has been diagnosed with leak in the cylinder head cover, which has resulted in engine oil leaking directly onto the exhaust manifold. This leak produces significant smoke and a strong burning oil smell while the vehicle is running. There are numerous reports on Mazda owner forums describing the same issue occurring in Mazda CX-5 models. Some owners even reported instances of minor fires or active burning under the hood due to oil contacting hot components. Mazda released Technical Service Bulletin TSB #SA-031-21, which includes a redesigned cylinder head for the 2018–2019 CX-5 models. This bulletin demonstrates Mazda’s awareness of the design flaw. The TSB only covers turbo 2.5L engines and not normally aspirated engines. There is substantial evidence that this is a widespread defect in these model years, unrelated to owner misuse or vehicle mileage. Mazda should take full responsibility by issuing a formal recall or providing an extended warranty to address the problem and prevent safety risks.