It may not be that there is an obstruction that is causing the problem, a none flushing loo of the older kind works with a diaphram to suck up water to begin the syphoning process, the diaphram is a thin piece of plastic sheet properly shaped and can after time become brittle and crack letting air in, it be bought as a replacement, however if you are not handy then unless you can take the insides apart to see how the diaphram is fitted leave well alone and ask someone who can,
Its only half an hours job so if you have to call someone in it won't cost an arm and a leg.
Duncan Quick, October 2007
