Bubb

The bubbling problem is not due to water consumption, if rather because compression is passed to the cooling system and this originates from three causes:
1.- The ocabezote head packaging is burned.
2.- The head or head is crooked as a result of a heating
3.- Irregularities of the Planicity of the head or the monoblock.

In any of the three you will have to disassemble the head, check the plainness that is within the tolerances indicated by the manufacturer, change the packaging.
It is important to check that I originate the previous warming so that it is not repeated again.
Check it and tell us
greetings

Friend this same problem can cause an increase in fuel consumption.

Yes, definitely, since if you have compression leakage for the cooling system your engine is not working 100%. It is also possible that you have an engine failure and this causes you lack of power, with an increase in fuel consumption, heating and therefore deformation of the head or burned packaging.
If you have mechanical knowledge you can perform another type of tests, but if you are an amateur I suggest you carry it with an expert.
Greetings

Friend I have some experience in mechanics, but I can only measure compression to the engine, what is another test?

Thanks for your help

Apart from what you tell you that you review it begins by reviewing the thermostat that you are not hitting it is supposed to check that the fans are working and good radisor and tapom and that of the rowing and asked what an extraromous reheated.