Oil leak near rear main seal onto rear O2 sensors, oil pan or RMS?

[Seaneezy]

I don't have a good picture since I wasn't thinking and cleaned up the leak before considering the possibility of a rear main seal leak.

Rear main seal replaced by local mechanic ~3 years ago / 7k miles (car was sitting for months) when transmission was out for a rebuild. I replaced the oil pan gasket in the same year (new bolts, carefully torqued with in/lb wrench and proper pattern).

Could an oil pan leak lead to oil covering the rear o2 sensors? the gasket is dry where its accessible.

I have circled the areas where oil is most prevalent before I cleaned it up (middle spot in picture is the access port, a few drops)

 

[steve30]

I had a similar issue, ended up being my front turbo drain fitting with a slow leak (due to blocked oem pcv/valve cover). Wile driving the air would push the oil down the oil pan gasket and splatter onto the secondary O2's. Its pretty easy to see if its the rear main seal, just shine some light up the opening and if you can see oil behind the flywheel then its most likely the rear main seal. You could even stick your finger up there and feel for any oil.

On another note, if you have an oil leak somewhere I would also check your PCV/valve cover because that could cause excessive crank case pressure and make the oil find the easiest way out. I recently updated my dual catch can setup from VTA to adding an external PCV setup and its a huge difference.