Well, last night, I decided to do another complete oil change with nothing different to the usual. When I tightened the oil hose bolt (2) in the picture to 10 Nm / 7.2 ft·lb However, things didn't get to 10Nm, before the bolt snapped. Thankfully, I didn't strip the thread on the case. Now my question - I believe my torque wrench to be working just fine (precision instruments model only months old with not much use). I did not clean the bolt of old oil. Could the engine oil have resulted in a faulty torque reading much lower than normal, or did I get it wrong and the torque setting should be lower for this bolt? Don't want to break another, or risk something worse Also - any ideas on what the replacement size/thread is?