I have Ford Focus MK3 diesel 1.6 zetec s 

When the car is cold I have no coolant in the tank but when I take the cap off it’s still pressurised and all the coolant comes back into the tank. The coolant is also black. 

I have had a pressure test done to see if it’s the head gasket and has been confirmed ok, the oil cooler has also been changed and the coolant has been flushed twice and there is no change?

Have been told it could be to do with the egr valve cooler?

It has also started going above middle temperature and loosing power but not all the time.. 

Just wondered if anyone has experienced this?

Have you had a sniff test done or just pressure?  Sniff will tell you if the EGR cooler is leaking.

Has it turned black or was it black when you bought it?  Someone probably added some stop-leak/K seal if you bought it like that.

I will ask the garage today if they done a sniff test, if not I will get this done

from what I remember It wasn’t black when I bought it 

I am having the same problem with a Ford Focus 2015 1.6 diesel, 52k on clock, when the engines hot it’s sucking In the coolant, when the engines cold and you release the cap it fills the fuel tank, with a dirty coolant colour, I’ve had the sniff test done few week ago an they said it was fine apart from dirty, but later told me there sister garage as seen this problem on a few Focus and it is a new head gasket

Hi what was the out come in the end thanks