oil in intercooler on 95 sc

ive got a 95 sc with 157000 miles i recently installed a water pump and when i disconnected the intercooler it had a oily film in it,blower too. since ive noticed it drips out of the lower joint between intake pipe and the innercooler. i checked the innercooler fluid a while back and it was full. From the stains it left at dads house it has been doing it since i got it approx a year ago, he hates oil stain in his driveway. pcv valve is new. any ideas? would appreciate the help.