Need a little help with the 420 sel!

[1988 benze]

I have bought a 1987 420 sel. my problems are ...1) I have to fill it up with oil more than twice a week. 2) my fan makes funney sounds and starts and stops spinning(I think i need a fan cluch). 3)idle problems. However bad this sounds, the car runs good. I'am trying to restore the best i can. I put new brakes,spark plugs and wires,distruber,oil change with filter,new gas filter, transmission filter and front end alignment.MY questions are, what can i do to stop useing so much oil every week. i have 180,000 on this car and i want to keep it. Any insight would be very helpful.....