Ford (F) is facing an engineering analysis by the National Highway Traffic Safety Administration over timing-belt failures affecting 135,551 vehicles, NHTSA said Friday.

The investigation covers certain 2014 to 2017 Fiesta and 2015 to 2018 Focus models with manual transmissions, as well as some 2018 to 2021 EcoSport and 2016 to 2018 Focus vehicles with automatic transmissions, the agency said.

Degrading timing belts can generate debris that blocks the oil-pump screen, causing engines to lose lubrication and potentially lose power or seize while in motion, and 355 incidents have been reported, it said.

Shares of Ford were up 1.5% in Monday trading.

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