According to the Haynes manual there should be about 7 litres of coolant. If you got 1 litre out and then 4 litres in, it could be the head gasket is leaking. Check the oil level, the oil filler cap inside for mayonnaise, steam from the exhaust, check for any leaks.
oil level / filler cap /steam from exhaust all seem to be okay , yesterday i discovered a heavy leak which seemed to be coming from one of the two hoses just below the small bleed bolt , it wasn't coming from the bleed bolt , so i wiped it clean & ran the engine, to my surprise the leak stopped ,
at one time i took the header cap off & water was overflowing from the tank , took the car to two local garages expecting them to know about the air lock problem & if all the coolant comes out at once how much the would expect to put in ,but never got a confident answer
anyway car is now running okay will keep an eye on water level , havn't put any coolant in yet just water will it be okay to run with just water for a week or so till i can be confident the problem is sorted