The contact owns a 2018 Ford Fusion. The contact stated that while his wife was driving at an undisclosed speed, there was an abnormal sound coming from the fuel tank. The check engine warning light was illuminated. The vehicle was taken to the dealer and was diagnosed with a coolant sensor failure. The coolant sensor was replaced; however, the failure persisted. The vehicle was taken to an independent mechanic who replaced the coolant sensor. The contact stated that recently, the failure had recurred. The vehicle was taken to a different independent mechanic, who diagnosed the vehicle and determined that the engine block was cracked and needed to be replaced. The vehicle was not repaired. The manufacturer was made aware of the failure and referred the contact to the NHSTA Hotline for assistance. The contact related to the failure to the Customer Satisfaction Program: 21N12; however, the vehicle was not included. The failure mileage was approximately 115,000.