Hello I have a 2000 ES 300 with a very bad oil leak coming from the left bottom corner of the engine as evidence by a pool of oil on the ground in my garage. I believe this to be perhaps a valve cover gasket but im not quite sure. I took a look under the car and saw oil drips on the bottom of the device connected by the green belt in the picture.



Anyone know what could be causing this?

 

That device is known as a Power Steering Pump and the belt is what drives it. There is a fluid reservoir for it on the passenger side (next to your coolant bottle). See if you're low on power steering fluid, that would indicate a leak.

Otherwise, it could be your engine oil seaping through a bad valve cover gasket. These engines are known for bad rear valve cover gaskets, and because the PS pump is right next to it, it gets a little confusing.