Hello all, I have a late 80s model L235 with 700 hours that runs great, but has started making oil. Somehow diesel has started making it's way into the crankcase. From what I know, diesel either gets into the oil via leaking injectors or a leaking injector pump. Since the problem has just started in the last few hours of use and the tractor is still running an it has (no issues) where would exprerienced individuals recommend I begin narrowing down the source of the problem?