1991 Chevy Caprice cars totally dead all of a sudden

Car just died one day while driving down the street, all lights and radio on, wouldnt take a jump to start. Mechanic sells me a 500 dollar distributor change. Two months later starter goes down, car had minor oil leakage problem and strange burning oil smell, somewhere between exhaust and antifreeze and oil smell. Heater control valve goes down, I replace. Take car in to ck out oil leakage problem, leaking from seal and oilsending unit, replace oil sending unit, leaking stops. 6mos later, heater control valve goes out again, they claim it was probably a defective part. 1 month later, car just wont start, lights and radio on. No noise at all type, no starter kickin over. Service engine and battery lights on. Tow service jump starts car, and says, oh, you just need a new battery. No lead up problem starts. Put new battery in, car fires right up. Still have odd oil burning smell. 3 days later, driving down the road radio goes out then engine and lights, totally dead. Any suggestions wher to start? Cant afford mechanic bending me over! Help please!