Put the best quality oil in it you can afford. I swear by Mobil 1 5W 30 was VSTL now called ESP formula (for cars with DPF's - low ash). I've had 3 530D's with the M57 engine (same as M47 but two more pots) I've got so much mileage out of them and the turbo's it's unreal. I know a lot of other guys in the trade believe it also, my current 530D has 165K and inside the oil filler is pristine (like factory), I've had the rocker cover off once and it was like a new build. My 2nd 530D and I parted at 286K factory turbo - no shit.