Is it normal for the expansion tank to bubble in a Ford Fiesta 1.0 Ecoboost?

After we test drove A Ford Fiesta 1.0, we looked under the bonnet and the expansion tank was bubbling. We were told this is the car cooling down as it has an ecoboost in it, we would like to know if this is normal, please?

Asked on 31 October 2017 by Mr A Brans

Answered by Honest John
Yes, the degas pipe from the turbo feeds superheated coolant (steam) back into the expansion tank where it condenses. Any leaks in that pipe you're in serious trouble, but normal for the degas contents to enter the expansion tank at the top.
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