So, my partner and I bought a focus, unfortunately from a private seller! (Won’t be doing that again), within the first day I noticed the coolant was disappearing, lots of inspection, couldn’t find the fault visually, so took it to an engine specialist, turns out the cylinder head was cracked!! Replaced that, and had full engine rebuild, still losing coolant???? 
egr cooler has been taken off and inspected, radiator too, along with thermostat and housing, all pipes checked, no issues with any other components but it’s still losing coolant, the car drives lovely, you wouldn’t even be able to tell there’s anything wrong with it until you look under the bonnet and see the expansion tank is empty! We are getting seriously fed up of blindly throwing money at this car 😢 

we did go back to the seller within 24 hours to ask to return the car and get our money back, he told us to f*** off!!! 

1 hour ago, Romi said:

within the first day I noticed the coolant was disappearing, lots of inspection, couldn’t find the fault visually, so took it to an engine specialist, turns out the cylinder head was cracked!! Replaced that, and had full engine rebuild, still losing coolant???? 

So was the head actually cracked or was that just a misdiagnoses ?

The expansion tank filler cap is a known problem on many Ford models. They fail to seal properly, which allows the coolant to escape out the overflow. Even the expansion tanks themself are prone to developing hairline cracks which allows coolant to leak out when hot and under pressure.

Yes the head was actually cracked, it failed multiple pressure tests. Whilst on and off the vehicle. Surely the system wouldn’t pressurise if the cap was the issue though?