Importnights

hi iv got a 1994 import, i have been having problems with random overheating from time to time, the car was due a timing belt change so thought id give it a birthday and while i was doing belt i would do water pump and change rad thermostat and fitt a samco hose kit. i have done this today however when cleaning and flushing system i noticed there was a blockage in my header tank. dont really no the best way to describe it, the pipe that goes on below the cap overflow pipe on front of bottle. i have soaked the bottle and cleaned and have had some bits come out of that connection i was wondering if it has some kind of one way velve in it for what ever reason due to there still being something in there and i can blow down but not suck back up. would really appriciate it if someone could shed some light for me as i have been sitting enduring xfactor picking away at the expansion bottle for too long now and dont no if i sould persist or not thanks dan