Changing the Engine Oil Level Sensor

Brian had a problem where oil was leaking from the oil level sensor on his 2003 LS.  The dealer failed to fix the problem on the first visit.  Rather than spending another day at the dealer, Brian fixed it himself.  At first, he tightened the sensor.  When that didn't help, he picked up a new sensor.  He discovered that they had changed the part number and now had an “improved” version.

The oil level sensor is mounted on the oil pan.
Remove the electrical connector.  You will have to lift up the clip that is hidden in this recess.  Brian used a spring clip to disengage the clip.  Drain the oil (might as well do an oil and filter change).
Factory installed sensor.  Note o-ring.
Replacement sensor.  As seen here, the new sensor now has a washer with a second seal around it.  The original O-ring is still there between the washer and the nut part of the sensor.  The oil pan has a slight dimple around the threads into which the original O-ring or the rubber part of the washer seen here will mate to.

The new part number is 12579985 and listed for $48.91.
Reinstall and tighten to 12 ft-lb (16 N-m).  Reconnect the electrical connector and fill with oil.

Brian continues, "After my initial installation I still had a small drip so the sensor was removed a second time and reinstalled with sealer on the threads, carefully applied, so as not to contaminate the oil supply.

"Having now gone thru the process, I would recommend just applying thread sealer, perhaps adding your own metal washer and skip buying the new sensor.  With the metal washer on the sensor, the tightening process works a lot smoother."
Thanks Brian.