*2009 E350 Oil Leak Diagnosis

[kbaruch1]

I have an '09 E350 with 89K miles. I drove the car after being out of town for a couple days and noticed some smoke coming from the passenger side of the engine. I opened the hood to find the source of the smoke and nothing looked unusual. The engine was clean and there was no sign of oil anywhere. The oil on the dip stick was not at a concerning level, but looked gunky. I stopped and put a quart of oil in with the plan to get the oil changed this week. While driving home, the smoke from under the hood (still on the passenger side) steadily increased to the point when I arrived home it was pouring out of the front of the car. When I opened the hood, there was oil all over the left side of the engine and quite a bit in the pan at the bottom. My father thinks it is the oil level sensor since the smoke continued even when the car was not moving, and the engine sounded fine and was not making any unusual noises. Any suggestions on how to proceed would be greatly appreciated. Not sure if I should have it towed to a local mechanic or try to replace the oil sensor myself. Help!