2002 toyota carolla black oil and losing 3 qts oil every 3 days with no leaks

I'm surprised an engine that worn out even runs. Your rings are bad. If the body is in good shape, get a reman long block

GW

If you are really using oil as fast as you say, you should never change the oil again because it is always fresh and as clean as it will ever be. You should be talking to your boss because he should have at least a clue as to why the oil is getting burnt.

Honestly, if you are using a quart per day -- 3 qt. every 3 days is 1 qt per day -- then you should have a huge mess on your hands, pools of oil on the floor or a massive build up of oil on the rear panel of the car, that should be a clue as to where the oil is going.