tracking down oil leaks

[wildfingas]

I have the infamous oil on the bell and saturated inspection window. Not oerly concerned but would like to know where on the engine to check for what may be leaking like sensors or o-rings. I was poking around looking to see if anything was collecting in the valley but didnt see but I also didnt really get into it to much.

I dont think its the rear main based on the fact that they are not that common and from what I read on here it usually leads to o-rings on the HPOP or a sensor somewhere. In my experience in automotive the oil seals generally hold up well on MOST makes.

So I guess I'm looking for where to look and what I am looking for.