My diesel 2011 Ford Mondeo Titanium hatch has been a great car, but it's not without its niggles. The main one is that the cabin fills with strong diesel fumes when I drive with the sunroof open. Ford has checked the car over on several occasions, but can't locate the source of the problem. I am frustrated with having to take the car to the dealer regularly for "further evaluation". Are you able to shed any light on this matter?
It's unlikely that exhaust fumes are being sucked back that far up the car, so it's more likely to be fumes blowing back from the engine and probably coming in through the air vents in the dash. Next time you drive with the sunroof open close the vents and see if that stops the flow of the fumes. The dealer is the only person who can fix it for you, so persist with him, and perhaps ask for a meeting with the service manager so you can explain your frustration to him and urge him to solve the problem.