318 small oil leak

maybe a engine crank main seal?
Or the oil pan? A tips when mounting the pan is to fastening the bolts with a torque wrench in a cross patten.
But the oil leak can come from many places, dip stick? front cover? camshaft seal? valve cove? its hard to tell.

But i don't think it is any danger, it probably only give you some rust protection when you drive around.