Just reread the post mentioning the oil and got a question or 2. It says Where is way back in the housing exactly? Opposite the hole where the fan fits or towards the resistor, or somewhere else entirely?

 

Straight back from the fan hole just under the trap door.

 

Ever happen to spill any oil products up on the cowl where the fresh air vent leads to? Only other thing I can think of would be it being sucked through the vent in the passenger foot well, but that just doesn't seem very feasible to me.

 

Previous owner attempting to lubricate a squeaky blower motor perhaps?

 

"Previous owner attempting to lubricate a squeaky blower motor perhaps?"

Thought about it last night where in my Ranger that flapper was stuck and had to lube mine up. But I used a dry PTFE lube so it wouldn't run out. I haven' had the truck that long so who knows what the POs did.