Atlas copco GA160 oil pressure goes low in unload,high oil temp

hello , 

i am running a GA 160 Atlascopco oil screw compressor .

The oil injection pressure of this compressor became very low when unloaded , 

 the pressure goes as down as 7 psi , ( the compressor does not trip in this point, this is another issue ) the oil reservoir pressure goes to 20 psi and less . Oil injection temperature also high up to 95 (where normal is near 65 )

I have changed the oil filter ,oil and oi/air separator , checked load /unload valve 

the problem is not solved yet.

Thanks 

TA