water pump replaced at 65000m & leaking again 73000m. dealer says engine head oil leak caused second failure; should I fix the car and sell it - don't want to replace pump every year

if the car is starting (up to 80km/hour), can the root cause be 3 injectors and ECU defects?

Thanks for your advises,

And what is fair price for each

The vehicle is 2 years old and has barely been used - under 5000 km. (A courtesy check / top up of the engine was done at the dealership last year). It is parked most of the time. I have been using it for 2-3 weeks. When you touch the inside of the exhaust pipe, you get wet black soot / oil residue on your finger? Is it something serious or would a good long drive at high revs clear it and get the engine running OK.