The Oil pressure switch is the device which will have to warn you when the oil pressure drops below a pre-set level.

If you switch the ignition on and the oil pressure warning doesn't come up, the oil pressure switch is broken and needs to be replaced. Vice Versa.. if you find the oil pressure warning to be flickering or even constant while you know the engine has enough oil pressure, the switch is broken..

But... there's also something else.. these switches are very basic mechanic switches. They've been on an engine since it was produced and you will find the detection level to be shifting over time. You might just want to replace the switch every.. say five years for a piece of mind..

This is the original Rover switch with either a 1/8 NPT thread or M12 thread. Rover has changed the thread during production. We know later cars have M12 thread, but we don't exactly know the engine number where they have made the switch..

Genuine X-Part (Rover) part.