U.S. auto-safety regulators have launched a new investigation into Honda’s 3.5-liter V-6 after hundreds of complaints that connecting-rod bearings are failing and causing engines to seize—an issue that could lead to crashes or fires. The National Highway Traffic Safety Administration (NHTSA) opened Preliminary Evaluation PE25008 on August 20, covering an estimated 1,410,806 vehicles across five Honda and Acura nameplates from model years 2016–2020.
What’s Under Investigation
NHTSA’s Office of Defects Investigation (ODI) says it has 414 consumer reports of connecting-rod bearing failures in vehicles equipped with Honda’s 3.5-liter V-6, plus 2,598 reports from the manufacturer. The agency has logged four incidents involving crashes or fires and no reported injuries. The affected models are the 2016–2020 Acura MDX, 2018–2020 Acura TLX, 2016–2020 Honda Pilot, 2018–2020 Honda Odyssey, and 2017–2019 Honda Ridgeline. Problem description in ODI’s filing: “Failure of connecting rod bearings leading to complete engine failure.”
How We Got Here
NHTSA previously examined failures in this engine family as part of Recall Query RQ24013, which looked at whether complaints were tied to a 2023 Honda recall (23V-751) addressing a crankshaft manufacturing defect. Investigators now say the newly reviewed bearing-failure cases fall outside the scope of that 2023 recall and do not appear to be caused by the same crankshaft issue, prompting the fresh preliminary evaluation.
Automotive outlets and industry briefings note the probe targets Honda’s widely used J-series 3.5-liter V-6, which powered a large cross-section of the brand’s family SUVs and minivans in the late 2010s—one reason the potential population is so large.
Why it matters
A failed connecting-rod bearing can starve the rotating assembly of lubrication, create metal-on-metal contact, and lead to rapid engine seizure. In motion, that raises the risk of loss of power and fire from catastrophic internal damage—circumstances NHTSA treats as potential safety hazards.
What happens next
A Preliminary Evaluation (PE) allows NHTSA to gather data from the automaker and the field. If warranted, the agency can escalate to an Engineering Analysis and ultimately press for a safety recall. For now, no new recall has been announced; the investigation is ongoing.
What owners should do now (user-intent guidance)
- Check your VIN on NHTSA’s recall website periodically to see if your vehicle becomes subject to a recall or service campaign as the investigation proceeds.
- Watch for symptoms of bearing distress: new engine knocking/ticking, metal shavings in oil, oil-pressure warnings, sudden loss of power, or stalling. If present, stop driving and contact a dealer. (General guidance based on the reported failure mode.)
- Document repairs and complaints. If you’ve experienced an engine failure, file a complaint with NHTSA; owner reports inform ODI’s analysis.
The bottom line
NHTSA’s PE25008 broadens federal scrutiny of Honda’s 3.5-liter V-6 beyond a 2023 crankshaft-defect recall, citing hundreds of consumer complaints specifically about connecting-rod bearing failures in 2016–2020 Honda/Acura vehicles. The agency’s findings will determine whether a new recall is necessary; until then, owners should monitor for symptoms, keep records, and check VIN status for updates.
