Late last year I had to replace the injectors in my 2007 Mazda BT-50. The mechanic who has serviced the car since 2009 told me there was a problem after replacing the timing belt at 123,707 km and advised me to have a diesel specialist check the injectors as there was an oil leak that seemed to be coming from one of the injectors. The diesel specialist advised me that I had a loose injector and that it had probably been that way since new. He said he had only encountered this once before in his time as a diesel mechanic. Before I contact Mazda to discuss the issue I thought I would ask you for your thoughts.
I wouldn't bother contacting Mazda, the car is seven years old and there's no proof that anything was amiss with it from new.