I have a 2009 Mazda 6 2.2d (183bhp). I have been reading a fair bit about problems with the DPF on these cars, so when the light started flashing I immediately checked the oil which was exactly where it should be. Car has done 97k, was running perfectly and does a 60 mile a day commute on the motorway and service is not due for another 2000 mile (car has fsh). Oil level checked at least once a week has never really fluctuated below or above the full mark. No reason for the DPF to come on and car did not go into limp home mode. Booked it in for a service at my local Mazda dealer and by some bizarre coincidence the earth lead bolt fractured on the motorway yesterday, the day before it was due to go to the garage. After being brought back by the rescue services I remounted the earth lead and started the car. It makes a terrible very loud squeaking/banging noise. Checked the oil level and now it is way way over the x mark. Is the noise because the head gasket has gone or something? Has the sump been filled up with diesel as a result of the car effectively being bump started at 70mph (because the earth lead came off, the engine would have been turned over without ignition). Any suggestions gratefully received.