On some cars, such as my 2000 Taurus with the Duratec Engine, the crankshaft position sensor goes into the timing chain cover horizontally, right next to the main seal--the oil is hot and the pressure is high. In trying to locate the source of an oil leak, I discovered this sensor was the culprit. It was hidden by a heavy-duty cover, which required removing the right front wheel, fender liner, and rotating the alternator for acccess.

The problem with the sensor was that the O-ring's I.D. was too large, which allowed the O-ring to rotate easily on the sensor. When I measured everything, using a Vernier Caliper, the O-ring's I.D. was .004-inch larger than the diameter of the grooved shaft. This caused the oil leak. This has been a long-standing problem with this car. I replaced the original Motorcraft sensor 2 years ago with one manufactured by BWD. Both of these sensors suffered from the same manufacturing defect. The AutoZone DuraLast sensor that I bought today, made by Wells Electronics, got it right.

I'll be installing it tomorrow and I will let you know if this solved the problem.

After 300 miles of highway driving since I replaced the CKP Sensor, the problem is gone.