Found puddle of oil leaking from timing belt cover on a 2007 XC70. Once cover removed a threaded half dollar size plug w o-ring dropped to the ground. Can’t find any obvious place from where it came nor reference in any online parts schematic. Looking at 2.5T engine pix online I suspect it is found above harmonic/pulley. That needs to be pulled-off to replaced plug I assume. Anyone familiar with this plug? Thx in advance.