This was my pass write up on the dreaded oil leak, hope this also help...
https://www.mazdas247.com/forum/showthread.php?123827661-HELP-!!!-Oil-Cooler-Spin-On-Oil-Filter-Conversion-420-Seal-
https://www.mazdas247.com/forum/showthread.php?123855052-Oil-Cooler-Replacement