Esiest thing is to tghten all ur piping's rubber. If cannot, dismantle ur intercooler and suppress into water to check for bubbles. if alot comes out then throw away & go buy a trust intercooler (Joking).. Easiest way is to bring it to an experienced mech of radiator sifus..
I'm thinking to buy a S15 and going to have a look 1 unit in Cheras this Saturday. Seller put a price tag of 110k and it is yr 2002(unreg).btw its a turbo spec. Can anyone of you here give me some tips...