My first 4/4 Sport had a leak from the oil pressure tapping on the back of the cylinder head. The brass fitting has a taper thread and if over tightened will snap like a carrot
- if the fitting is leaking unscrew carefully (you can shear it off unscrewing as well as tightening ) clean the threads and replace with a smear of gasket grade silicone sealant, tighten gingerly!
If the switch is leaking then it will probably have to be replaced
