Is this sensor missing the o-ring, or is it in the recessed part? If in the recessed part, do I carefully pry up and replace?

 

It's in the grooved section. I used a pick tool to get mine out. I had an o ring kit from when I replaced my AC compressor, so I found one of a similar size, cleaned up the sensor and surrounding area and dropped it in. So far so good, the area has been dry.

 

Thanks very much.