I have recently noticed largish oily deposits on my garage floor. I obviously checked the engine/ gearbox for any visible signs of leakage, but could only see some minor/older oil seepage on the engine block.

On examining the oily patch closely I found that the "leak' was coming from the rear of the vehicle. In fact, there appeared to be some recent seepage from what I think is the fuel Reflex pipe which vents opening into the wheel arch area below the fuel filler cap.

I am assuming this reflux pipe to be a fuel tank breather?? If so, what would would be causing diesel oil to be leaked out through this pipe.

I may have the answer to this, in that since purchasing the vehicle I have never been able to properly lock/seal the fuel filler cap. Could this be the problem. Cheers