I've heard rumors that since piezo-injectors in N57s proven to be unreliable, BMW switched back to solenoid-type injectors in later engines.
Now I see piezo-type in B57 specs.
My question is what type of injectors are used in BMW diesel engines since N57, and how reliable are they (i.e., are they all tend to leak and flood an engine when fail, like first models were; and their reliability in general compared to solenoid-type)?
Also, what approximate mileage resource piezo-injectors have? Although this is not an exact parameter, and it's more about an experience, I'd like to know at what mileage on average they require replacement for the first time. Is it 50k, 100k, or 200k miles/kilometers? Should I reserve funds for them when purchasing a car 100k miles old?
Can they be repaired at shop, or they are one and done?