F150Mustang - 5/13/2021 11:15

Yesterday hauling corn I developed a small oil leak. It’s a 2002 6nz C15. I determined it was above the oil filter housing, and below the oil cooler. This morning I got the cooler off. I’m guessing it was the Oring towards the back as thats where most of the oil was sitting. My questions are, should I pull the oil filter housing also and put new gaskets on it?? It doesn’t look like it leaked between the block and housing. Is it common for one of the orings to fail like that? I hear when the cooler fails it’s a mess. That’s the next question, should the cooler be replaced while it’s off or run it? 652,000 miles. Original as far as I know. Any other thoughts on it??

Pics are of it apart before and after I cleaned it.