Two times in the last week or so I've noticed some thick, brown/black liquid puddled at the front corners of my fridge (Frigidaire BHGS2644KF1).

I've pulled the unit out and there's puddles of this stuff under all 4 wheels and only under the wheels. It's not water and it's not a leak from inside the compartment. This stuff is pretty thick and when wiped up it looks yellow on a rag so it seems petroleum based to me. Has a slight oily smell to it as well, not food based.

I know there are leaks that can occur, but it seems so odd that the only place it shows up on the floor is under the wheels.

The fridge functions fine....no fluctuations in temp or changes in operation that I've noticed.

Any ideas of what this could be?