The National Highway Traffic Safety Administration has opened an investigation into some 2021 Ford Bronco SUVs, according to documents published last week. Should the investigation result in a recall, as many as 25,538 Broncos could be affected.
NHTSA said it received 26 complaints from owners about "a loss of motive power at highway speeds with no restart," according to the investigation bulletin (PDF). All of the problematic SUVs are 2021 Ford Broncos equipped with the 2.7-liter EcoBoost V6 engine. The smaller 2.3-liter EcoBoost I4 engine is not part of this issue.
"This alleged loss of motor power is a result of catastrophic engine failures due to the valves failing," NHTSA said. "Ford identified the root cause as the valve 'keepers' not holding the retainer in place allowing the valve spring to detach from the valve resulting in interference between the valve and piston. This interference can cause an engine lockup."
Ford did not immediately respond to a request for comment.
It's important to reiterate that while this is an official NHTSA probe, it is not a full recall. NHTSA said it decided to open the investigation "to assess the scope, frequency and potential safety-related consequences of the alleged defect."