Exhaust smell inside the cabin

Owners reported smelling exhaust inside the car, usually under hard acceleration or with the air conditioning recirculating. NHTSA investigated for six and a half years, collected 791 complaints and 25 injury reports — and closed it in January 2023 having found carbon monoxide levels below accepted health standards and no safety defect. That answer is worth having in full, because the internet's version stops before it.

Symptoms

A smell of exhaust in the cabin. NHTSA's account of the reports: occupants smell it "some of which expressed concerns about exposure to carbon monoxide", and the conditions that bring it on are "operating the vehicle with full throttle applications (e.g. climbing steep grades or merging onto freeway ramps)" and "use of the air conditioning system in recirculation mode". The alleged symptoms in the complaint file "range from unspecified to loss of consciousness, with the majority indicating nausea, headaches, or light headedness".

Likely cause

Never established as a defect. Ford's bulletins treated it as a sealing question — TSB 12-12-4 of December 2012 "specified sealing and undercoating of certain areas of the rear floor pan and body seams, replacement of the left-side air extractor, and installation of rear lift gate drain valves", and TSB 14-0130 of July 2014 added software changes to how the air conditioning recirculation behaves under full throttle. Some owners "reported little or no improvement after the TSB remedy", which is what prompted the investigation.

How should it be checked?

Ask whether the sealing bulletins were carried out — they are bulletins, not recalls, so they will not appear on a VIN recall check and only a dealer history will show them. Then drive it in the conditions the reports describe rather than around the block: hard acceleration up a hill, air conditioning on recirculate. If you smell it, that is a reason not to buy that particular car regardless of what the investigation concluded — the finding was about the fleet, not about the one in front of you.

How can you check it yourself?

Drive it hard uphill or up a motorway slip road with the air conditioning set to recirculate, windows up, and use your nose. Then look underneath at the rear floor pan and around the tailgate for sealant that has been applied by hand — that is the bulletin work, and finding it tells you the previous owner complained.

The question to ask the shop

Were Ford's exhaust odour bulletins carried out — 12-12-4, 14-0130, 16-0166 or 17-0044 — and is there a dealer record? Has this vehicle had any rear-end body repair? Was it ever a police or fleet vehicle?