When I changed the crank position sensor I noticed it was wet with oil. This is evidence that the rear main seal is leaking. Am I right?
Will this interfere with the functioning of the sensor? It's an automatic.
It seems to start and run OK, right now.
Thanks.

More likely the rear cam seal and or rear cam seal plug if you have a block-driven distributor. Check the back of the head. The plug can come out and cause a CATASTROPHIC loss of oil. Very worth checking that it's in one piece and still installed. There is information on this in the FAQ.

The rear main seal would be leaking out the bottom of the transmission. Maybe, just maybe (but I really doubt it) a little could creep up if the RMS were leaking badly. But you'd get a lot more coming out the bottom and be losing oil to the tune of a quart every couple thousand miles or more.

The oil on the sensor won't interfere with its operation, but it will degrade the plastic and insulation on the wiring.

Cheers

Agreed, it should leak out of the bottom where the tranny bolts to the engine.


"But you'd get a lot more coming out the bottom and be losing oil to the tune of a quart every couple thousand miles or more."

More likely a quart every 500-1000 miles and sometimes much more if it's a bad leak. I had one go on my parents Jeep when I was driving it. Went through about a quart every 100 miles on 300 mile highway trip. Made a mess of the rear window too!

Was just the end of the CPS wet or was it wet by the wire harness?
usually a rear main seal leak will just travel Downward. I would check the little 'Puck' on the back of the Head.
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