Our 1660 this last harvest was starting to get like a dog , no power. We used good fuel and filters , air filters, and oil. The machine has 3950/hrs (cummins motor). The engine also seems to have a fair bit of blow by. Near the end the motor would go through about 1-1.5L oil in a 8 hour day. I was told it might be the turbo, but My thoughts are the motor is just in need of a rebuild. Also the injectors were replaced at not to long ago. any help is welcome. Thanks.