The contact owns a 2018 Ford Mustang. The contact stated that the check engine warning light was illuminated. The vehicle was taken to a certified mechanic who diagnosed the vehicle with a misfire in cylinder #1, and coolant leaking into the engine. The mechanic referred the contact to the dealer. The vehicle was taken to the dealer who confirmed the diagnosis and that the engine needed to be replaced. The vehicle was not repaired. The manufacturer was made aware of the failure and opened a case. The manufacturer referred the contact to the NHTSA Hotline to report the failure. The failure mileage was 49,000.