2010 BMW 528i

Bmw 528i for sale ,car still runs but overheating problem come after I start for 40 minutes and one of my mechanic already changed its water pump ,oil cooler,coolant box cap ,and thermostat and flush it but still water coming outside of cooling box ,I already spent 2200$ in these things and now don't want to spend any more, car market value is around 16000, that's why I selling cheap ,

$7,500