Remove air refrigerant circuit mk3

Good to all, I take the opportunity to introduce myself because I am new here.
Well now my consultation, a week ago I bought an MK3 golf to restore it, the car works but the girl who sold it to me told me to change the expansion boat herself and since then loses refrigerant liquid for the plug of the boat. I have been testing the car and has no leaks, or heated, nor has any symptoms that made me think that it is the Board of the Bill, so what I think is that it has air in the cooling circuit, I am almost certain of it because the circuit capacity is 6.3 liters and I have barely filled it with 4 liters. My question is how can I get all that air from the circuit? Because in this model I do not see any type of pothogue and I think it does not have. Thank you all I hope you help me, greetings

There has to be a bleeding but if it does not exist then bleeding without the lid of the deposit, you let the air leave, but if it happens that it is usually tapa, they are usually two thermostat problems stuck or a bit of compretion is put into the water system.

A truquillo because yes, I am given cases that do not have bleeding. Look a temperature difference from the tube entering and the one that leaves the engine. If there is a lot of difference with the hot thermostat engine.
And to take the air the fat tube that comes out of the radiator presses pumping and in the bottle you will show how the air is throwing.

Thank you, I will try what I have commented and I tell you if the problem was solved, comment in case someone reads it that the girl made cheap antifreeze! I recommend spending a little more and throwing organic antifreeze that is much better to the engine and endures the temperature better, because that type of cheap antifreeze is stained water with colors hahaha.

Good again, I tell you, yesterday check what you recommended, the temperature of the tubes is similar, there is hardly any difference. As for tightening the tube if it seems to throw air but does not completely expel it. A question that has emerged is whether that tube could throw refrigerant liquid, since it goes directly to the radiator that is where I think it has more air. I await your answers and thanks again