No pressure in the top hose? then check the small bore hoses that run from the back of the water pum p to the inlet manifold and to the heater matrix, the fine bore pipes from the top of the radiator to the throttle body and back to the inlet manifold for splits.
A leak on one fo the pipes to theinlet manifold menas the water runs onto the valley gasket, then down the back of the engine where you can't see it, that's if it doesn't evaporate.
Also when you fill it up, fill it via the small brass screw on top of the steel pipes that run the length of the engine, this is there to avoid air-locks. Fill it briskly to push air from the heater back through the engine rather than adding water to the header tank.
Use an antifreeze with a leak tracer in it, bright green or pink are best.
