Hi guys.

After I changed the thermostat and new coolant liqued, I noticed the next day a bobling sound from behind the dashboard which is where the coolant systems runs. The sound comes when I press a little bit on the gas-pedal and goes away shortly after.

I took it to the mechanic and he used a pressure machine to get the air out, by opening a valve behind the engine block. We have done that a few times and other methods to get air out of the system and we have checked if the Head Gasket was damaged by testing the coolant system for C02, but nothing was wrong there..

The bobling/flushing sound does still come, any suggestion for solving that?

Car is: Fiat punto 1.2 16v, Year 2002
The new coolant was a pinkcolor the old was blue.. does it have any factor?

This noise indicates you still have air in the system. When bleeding the system you need to have the heater controls set to high (turned fully to the right) so that any air in the heater matrix is expelled. Search for posts by Ziggy as he has described many ways to bleed the system.

Personally I find filling the coolant expansion tank to the top on 8v engine then bleeding from the rear bleed screw then the front bleed screw. Seal up the expansion tank start the engine and let it run a few minutes then bleed screw rear and then front screw again with engine running but watch for hot coolant on your fingers.

Shut down and once safe to do so crack open the coolant tank and draw off the excess coolant down to the max mark. Seal it up and run the car up to temp i.e when fan cuts in. This always works for me although I once dropped the bleed screw under the car, stuck my finger in the hole and started to yell for my wife to come and locate the bleed screw under the car. My finger got bloody hot stuck in that hole but it amussed my wife no end.

darashen said:

This noise indicates you still have air in the system. When bleeding the system you need to have the heater controls set to high (turned fully to the right) so that any air in the heater matrix is expelled. Search for posts by Ziggy as he has described many ways to bleed the system.

Personally I find filling the coolant expansion tank to the top on 8v engine then bleeding from the rear bleed screw then the front bleed screw. Seal up the expansion tank start the engine and let it run a few minutes then bleed screw rear and then front screw again with engine running but watch for hot coolant on your fingers.

Shut down and once safe to do so crack open the coolant tank and draw off the excess coolant down to the max mark. Seal it up and run the car up to temp i.e when fan cuts in. This always works for me although I once dropped the bleed screw under the car, stuck my finger in the hole and started to yell for my wife to come and locate the bleed screw under the car. My finger got bloody hot stuck in that hole but it amussed my wife no end.

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haha