The contact owns a 2018 Ford F-150. The contact stated that upon starting the vehicle, there was an abnormal rattling sound coming from the engine compartment. After the engine had reached normal operating temperatures, the rattling sound ceased; however, the failure became a regular occurrence. No warning lights were illuminated. The vehicle was taken to an independent mechanic, who diagnosed a failure with the cam phasers. The vehicle was repaired, but the failure reoccurred. After investigating the failure, the contact related the failure to Customer Satisfaction Program: 21N03. The manufacturer was notified of the failure, a case was opened, and the contact was referred to the NHTSA Hotline for assistance. The failure mileage was 44,000.