By David Shepardson
WASHINGTON (Reuters) -The National Highway Traffic Safety Administration said on Monday it has closed a probe into 411,000 Ford (NYSE:F) SUVs and pickup trucks over a potentially defective engine that could lose power without warning.
In July 2022, the U.S. auto safety regulator opened its investigation into Ford Bronco vehicles equipped with 2.7L EcoBoost engines over concerns of a faulty valvetrain.
The probe was expanded later to include other models including the Ford Edge, F-150, Explorer and Lincoln Aviator and Nautilus vehicles with 2.7L or 3.0L EcoBoost engines from the 2021 and 2022 model years.
Under normal driving conditions and without warning, vehicles may lose power and be unable to restart due to a faulty valve. NHTSA said it had 1,066 unique vehicle reports of the issue.
In August, Ford recalled 90,000 vehicles after the automaker determined not all valves produced were defective, and that most failures occurred in vehicles that had been in use for a short time.
Ford's recall fix includes a dealer inspection and a test to determine if the vehicle has not met a minimum usage level to identify if it was equipped with defective valves.
Ford said data indicates the vast majority of failures have occurred in cars before they had been driven 20,000 miles, with over half of all reported failures occurring before 5,000 miles.
Ford said the engine valves cracked and fell into the combustion chamber of the engine causing catastrophic engine damage and said the issue was due to valves that exceeded the designed specification for hardness, were brittle, and more likely to break, citing the supplier's manufacturing processes, according to the NHTSA statement.
The intake valve material was changed for vehicles produced after October 2021, Ford said.
NHTSA said the rate of reported failures related to the faulty valve issue has steadily decreased since November 2021.
On Monday, Ford noted it would provide an extended warranty coverage on the 90,000 recalled vehicles for 10 years or 150,000 miles, whichever occurs earlier. It also said it was unaware of any crashes or injuries as a result of the issue.
Ford shares rose 1.6% in trading on Monday.