Some older Ford vehicles pose 'unreasonable' safety risks, regulators warn

close video FOX Business Flash top headlines for August 3 Check out what's clicking on FoxBusiness.com. Some older Ford cars and SUVs pose "unreasonable" ​safety risks, according to federal regulators, warning that the timing belt may fail, causing them to lose ‌power or engines to seize. The National Highway Traffic Safety Administration announced on Monday that it has upgraded a defect investigation into 135,551 Ford vehicles from model years between 2014 and 2021 that are powered by the small 1.0L turbocharged three-cylinder engine due to an "unreasonable risk to motor vehicle safety." The three affected models, the Fiesta, Focus and EcoSport, have all been discontinued by Ford. The NHTSA said it ​was aware of 355 incidents alleging a low engine oil pressure warning light ​appeared just before a complete loss or reduction of motive power while driving. FORD RECALLS NEARLY 388,000 VEHICLES OVER SECOND-ROW SEAT INJURY HAZARD Some older Ford cars and SUVs pose "unreasonable" ​safety risks. (Photo by National Motor Museum/Heritage Images via Getty Images / Getty Images) NHTSA said its initial investigation revealed timing belt material may degrade and create debris that clogs the mesh oil pump pick-up screen, causing reduced engine oil pressure. The probe suggests failures can happen without sufficient warning and loss of power or engine seizure is imminent. Failures have been reported despite proper and routine oil maintenance, the NHTSA said. "Based on NHTSA’s analysis ​of the data, failure rates, information provided by Ford, preliminary engine teardown analysis, and precedent recalls ​regarding loss of engine oil pressure with the presence of driver facing warnings, (the agency) believes there is an ‌unreasonable ⁠risk to motor vehicle safety," the NHTSA said. FORD RECALLS MORE THAN 110,000 MUSTANG VEHICLES OVER WINDSHIELD WIPER, DRIVETRAIN DEFECTS The National Highway Traffic Safety Administration said it has upgraded a defect investigation into 135,551 Ford vehicles. (Getty Images / Getty Images) NHTSA's decision to upgrade the probe to an engineering analysis is a required step before it could force the automaker to issue a recall . Some drivers reported engine failures that cost thousands of dollars to fix. One 2017 Ford Focus driver reported being on a highway in Wilmington, Delaware, when the oil pressure light illuminated and within an eighth of a mile, ​the vehicle "lost ​all power and the ⁠engine began to sound like a tank." Data showed an average failure mileage of roughly ​70,000 miles, and 98% of the failures happened before ​the 150,000-mile suggested ⁠timing belt replacement, the NHTSA said. The three affected models, the Fiesta, Focus and EcoSport, have all been discontinued by Ford. (Jeff Kowalsky/Bloomberg via Getty Images / Getty Images) CLICK HERE TO GET FOX BUSINESS ON THE GO In June, Ford told the safety regulator it was adopting a non-safety customer satisfaction program for global vehicles with a 1.0L Fox Classic Timing Belt, cutting the maintenance interval to 100,000 ⁠miles or ​six years. Ford is offering reimbursement to eligible customers who ​previously purchased engine repairs or replacements due to a timing belt-related issue, the NHTSA said, although it was not immediately clear which ​vehicles are covered by the customer satisfaction program. Reuters contributed to this report.