Hi there.

As the coolant expansion tank of my Ford Fiesta mk6 (100 HP (1.6 16V)) had been defect, i changed it. I decided to change the coolant as well. First of all i drained all of the old coolant through releasing the lower plastic screw of the radiator. After that, while filling up the cooling system with the new coolant, i could pour only about 2,3 liter of that liquid into the system before the coolant expansion tank got full (to max). What i noticed is that no coolant came out of the upper plastic screw of the radiator (it was released), although the coolant expansion tank was full.

Could you please tell me what is the problem? I don't think that there is that much air in the system (there are about 2 liters of coolant left - more than 4 liters should fit into the whole cooling system).

Many thanks in advance

Best regards

FoFiBoy

I don't know, not very scientific but if it was mine I would try squeezing the lower and upper radiator houses to see if it prompts any trapped air to move (with the coolant cap off).

 

4 hours ago, FoFiBoy said:

First of all i drained all of the old coolant through releasing the lower plastic screw of the radiator.

When you say you drained all of the old coolant how much was 'all'? You obviously can't put more back in that you took out in the first place. Bear in mind that to remove the coolant you need a means by which air can get back in otherwise a vacuum can be formed stopping any flow. Note also that there'll always be some coolant left on the other side of the thermostat in the block, heater matrix under the dash and various pipes in between.