Re: EGR Tube nut Wrench.
Not sure about the size but you should start soaking anything that you have to remove with penetrating oil.
I tried to replace an EGR valve on a '97 Ranger. The nut there wouldn't come off even after heat, penatrating oil(s) and 2/3 of it was chiseled/cut away. Tire and wheel well were removed. I had to saw the ERG tube at the exhaust manifold because that nut was rusted solid to replace the whole thing.
I even bought a flare nut wrench that fit the EGR fitting. Took it to work and had a welder heat/bend it to get around the dome shape of the EGR valve.
'09 Ford Escape Limited, V6, 4WD