It could be that when you stuffed with a refigrant you have not done it at all: open the heating control in "heat" position so that this is also filled, open purgiers until it only comes out liquid and close, fill the boat to the mark and leave it started until it turns on the thermostat (if it had air it had the cylinder head, the level lowered at this time and will have to be added) let it cool it. If after this continues to bubble, we will have to think about a problem at the Board or the cylinder head (this if the engine was previously taken)