You will get water spilling out of the rad when you bleed it of air, it does make a bit of a mess but its worth it! Literally leave it running for 10-15 mins and it will keep splashing water out, this is usually the air escaping. Keep topping it up with water, if it calms to a pulse Put the cap on. If not put it on anyway , Check the header tank is full then leave to cool for a couple of hours. Recheck header tank (mine usually takes the coolant out of it during cooling) refill header tank and radiator And repeat bleeding process. Its a pain and it can take several attempts! The only other thing I found with my car i actually had to take off the pipes to the heater matrix, from the engine and fill it up separately! Again it makes a mess but my heaters werent working and now they work a treat