2013 Hyundai Sonata has a loud knocking noise from engine. Purchases 8/5/25 at 43K miles, currently at 44K miles. There is a Technical Service Bulletin, # 22-EM-009H dated June 2022 about an extended warranty but its time limit is questionable. Unknown and undocumented when purchased. Not listed as an official recall so not covered under warranty repair and the only course of action I have been given is install a new motor quoted at $15K from local Hyundai dealer. Further research shows that driving should be limited to avoid further engine issues/fires. Occurrence since January 2026. Progressively worsening. Cause for concern. Is there an official recall on for the piston flap pending? Unsure if accident noted below is due to the issue.