High Air- End Discharge Temp. & Oil Mixing with water

1) In My Plant Air Compressor High Air end Discharge temp is coming frequently even if i change the Oil and it is filled as per the Manual . My Compressor Type is LM 250 ( ROTARY) Ingersoll Rand Compressors. Please advise me some thing to do in my compressor so that the same fault will not come again .. 2 ) Oil Mixing with water : In my Compressor same type as above mentioned . I changed Separator Filter , Changed both Oil Heat Exchanger & Air Heat Exchanger & also changed Minimum Pressure Valve . But no use what ever i am filling the coolant in the compressors that is coming out of compressor in no time ... Please advise me on this toooo ...