[bryanrex]

I experienced an oil pressure sending unit failure earlier today. The sending unit somehow failed in an intermediate range where it would register 0 bar with the ignition off and between 0.5 to 1.0 bar with the engine running (depending on rpm). Obviously when I ungrounded the feed it registered at 5 bar.

At first I suspected an oil pump failure (very, very bad), but there were no loud noises coming from the engine so I simply removed and cleaned the sending unit with WD-40 and some engine gunk. The sending unit started rattling again when shaken, so I reinstalled it and everything worked perfectly. Apparently with age it can get gummed up (like an old carb float), so cleaning it out and tapping it with a hammer can save you some time and money. If it fails again I'll replace it (and re-post).