What are the symptoms of a faulty oil pressure relief valve?

[SteveW]

Found out the other day that my oil pressure switch is leaking at the screw thread where the wire to the light goes.
The switch is just over 3 years old so I’m wondering if it’s just switch failure or there is something more sinister going on?
Did over a hundred miles last Sunday, bike behaved perfectly, except the sprocket cover had about half a cup of oil in it which is now over the front lawn. 

Big thanks to Nurse Julie who sorted me out a replacement switch in mega quick time 

[Bryanj]

Just a bad switch probably unless the oilpressure is incredibly high and that would give bigger leaks

[McCabe-Thiele (Ted)]

Oil switch leaks / failures seem quite common again I guess its connected with thin oils & additatives they use.

My neighbours 3 year old Kia 4x4 oil pressure switch failed with the light staying on most of the time!
Kia wanted him to pay for the diagnosic oil pressure check - so much for 7 year warranty - it turned out cheaper to get his local garage to fit a new switch.

[taysidedragon]

I suspect that cheap Chinese switches are not made to the same quality standards of original Honda switches.

[SteveW]

Put the new switch in yesterday and did about 5 miles, no leaks at all.

The old switch still worked normally, it was leaking around the brass insert that the wire to the bulb is screwed to.

[ST1100]

The old switch still worked normally, it was leaking around the brass insert that the wire to the bulb is screwed to.

Resin does age, suffering due heat cycles and also might be sensitive to (modern) oil additives (ether comes to mind)...
Observing similar issues on resin sealed wiring exits of oil cooled alternators...