That is the water pump, common failure item as the car ages. Just above it is the idler pulley, I change the idler pulley and belt every 30,000 miles or so - the pulley is around $18 and if they fail at speed, they can take out the radiator and do other damage - seems way easier to just change it frequently

As to that amount of oil, I would think an inspection will tell you where it is coming from. We often have breather/valve cover leaks, but they dont product THAT amount of oil