A diesel Particulate Filter is intended to collect smuts on start up, then burn them off later in the car’s journey by injecting extra fuel into the combustion chambers. If there is no ‘later’ this does not happen and the extra fuel dribbles down the bores into the sump, contaminating the oil in there, and if it rises past a certain point, leaving the engine to run uncontrollably on its sump oil rather than its fuel oil. If you were not warned of this when you bought the car you may have a case against the dealer who sold it to you for selling you a car "of unsatisfactory quality". FIAT had a specific person to contact over this problem but has now replaced her with a standard e-mail address: customerrelations@fiat.com . FIAT has replaced engines in this circumstance.