hi all an ty for replies.
liquid is simply distilled water with just a coffe cup of CITROSIL in it(liquid total volume is like 3 liters),
rad is a giant full copper car rad(check my signature),so probably it is the source of all this air,
anyway problem seems to be reduced a lot,BUT,everytime i shutdown pc and turn it on say the morning after i see some bubble moving immidiately into the bubble trap,
so i start supposing a vacuum leak somewhere,could try to tighten everything a bit more,but it's a pain in the ass considering i should remove all tubing,tighten all fittings in place,
reset tubing in place and retightening compression fitting,plus all over again the air bubble saga. :/ pffffffff