Bubb

It is likely that measuring the compression will tell you that cylinder is failing, but for this problem I suggest you take a leak test, it is done with a team similar to a buoy which injects air to the engine and indicates you through the air confirming the diagnosis.
I hope I could help you

greetings

Indeed, I perform the leak test and told me that I had to accent valves, I will perform the work and then tell you.

Thanks for the help

Hello everyone who has collaborated on this topic, I have the final report.

After performing the work in the cylinder head (accentuated of valves and change of some guides) I have to tell you that when you remove the assault of the cylinder head it was in perfect condition. After this work the car is with a little more strength but the bubbling continuously the fuel consumption remains in 42km/galon (it is usually 55km/galon).
The entire cooling system was completely reviewed, the pipe was changed and the thermostat was removed and with this the problem of bubbling.

Gasoline consumption could not be corrected

greetings to all

Well, remember to place the thermostat, people tend not to take it into account only when the VWHICULO does and the ambient temperature low to 16 degrees Cent. Failure begins and that goes in gas consumption