Originally Posted by amc49
So why did the first one not, do ya think?
I don't know.
The adapter expands and contracts with the heating and cooling of the engine. Could be after thousands of times, it just failed to contract enough to seal the sensor, and began leaking. When I tried installing the new sensor, it had to go further in the tapered socket than the original depth to seal, which was not possible, since the soft metal of the adapter cracked, before it could reach that point.