More fun!!!
The car overheated on Saturday, and warned me so I stopped, and got towed home; the water was empty. My mechanic father in law took a look, and there seemed to be a leak at the front of the engine, by the EGR valve. He created a gasket, but the water was still going done, so he used a smoke leak detector, and it turned out there was a crack in the plastic of the EGR cooler (as was suggested on the Facebook Mondeo forum).
The whole EGR this is a rubbish idea, but the worst is that you can't buy the components separately. Ford only sell the entire EGR unit, for R30K; you can't buy the valve, cooler, or any gaskets on their own. However, you can buy the EGR cooler separately on Ebay, so that's what I did. My mechanic is going to Belgium, so I'm having it delivered there. R2K, plus R700 for postage from UK and customs (thanks, Brexit!). I'll use his BMW in the meantime.
There are four major known issues on the Mondeo/Fusion; I call them the Four Horsemen. First is power steering; second is the EGR valve; third it the EGR cooler; and fourth is the thermostat housing, which can crack like the EGR cooler. I've replaced the power steering. I've bypassed and blanked off the EGR valve. I'm getting a new EGR cooler. And, for the last, I've taken pre-emptive action by ordering the thermostat housing from Ebay, and it's been delivered to my daughter in the UK, and I'll collect it in May.
The biggest hassle here is that the manufacturers are selling components only as a unit. You can't buy separate parts for the components. For the steering rack, you can only buy a complete rack, you can't replace the circuit board, wiring, motor, or anything else separately.