You may have a broken wire to a sensor. As it flops around, it connects the circuit causing the intermittent buzz. Check the wire to each sensor. Or the sensor is right and signaling low oil
pressure, over heat or what ever and because the wire is broken (could be hidden by the plastic covering) and then it will temporarily connect giving the short buzz. The sensor works by closing the circuit causing current
to flow causing the alarm
to sound. Most probably a short to ground. But finding it is the rub. Good luck.