I have a VW 2.3 V5 in

The heater matrix, thermostat housing and a plastic pipe joiner were all broken.
I have changed the matrix, joiner and housing.

I am still having overheating problems. I have left the filler cap off for all the air to come out, and turned the heaters on.

The heaters are blowing cold and the header bottle is overflowing.

I checked the thermostat which was bought new and It wasn't opening so i took it out to check water flow with out it. I can't seem to get the air out.

Any ideas please.

Is there a certain bleeding process for these cars.