This concerns a 2019 Mazda CX5 with approximately 52,000 miles — the engine of this vehicle is the 2.5L naturally aspirated version. Driving the vehicle with the HVAC system on resulted in a burning oil smell coming through to the cabin. Upon owner inspection, engine oil was seen as coating the underside of the vehicle in various areas. The oil pan drain plug and oil filter were both found to be tight and not leaking oil. The vehicle was taken to a nearby Mazda dealership for inspection on 2/26/2025. On 2/27/2025, Mazda technicians state that the cylinder head on the vehicle engine requires replacement. Replacement is quoted to be in excess of $5000. Reviewing the issue online shows numerous similar cases of engine cylinder head failure. This vehicle comes equipped with cylinder deactivation which seems to have a higher rate of failure regarding cylinder heads and a potential design flaw with cylinder heads manufactured in a time frame of 2018-2020. Leaking oil could potentially start a fire as the oil drips onto the exhaust manifold when the car is at operating temperature.