I, too, just added the same OEM Ford Engine Oil Cooler system to my own 2018 XLT.
As "realscot2" experienced, I also had to replace the lower radiator hose, as well as install a different "Oil Filter Adaptor"... one that is constructed specially to accomodate the additional "Engine Oil Cooler" unit, which bolts onto the face of it. A set of dual-hoses is also needed to connect the cooler unit to the lower radiator hose.
As he mentioned, removing the air box assembly was helpful in performing the radiator hose swap. I also didn't lose much coolant after draining the radiator (only about 5 quarts total), which I saved and re-used once everything was completed. However, because adding the cooling unit and hoses increases the total amount of system capacity, I had to add another 4 more quarts of Yellow coolant, while following the Ford shop manual's recommended process for evacuating air out of the system, before driving it and then topping it off a couple more times as it cooled. I also had to add about a half-quart of additional oil, since the oil cooler itself fills with motor oil.
Lastly, and as he shared, there is VERY LITTLE room to do this work in, which was not surprising! I, too, had to use a mirror at times, as well as a magnetic 8mm socket, in order to get the 6 small screws in-place, before I could even begin to tighten them all into place. Ironically, the shop manual shows to tighten these small bolts to "67nm", but it would take a miracle to even begin to get a small torque wrench in there, much less to be able to read the darn thing. Since it took a lot of torque to initially remove the bolts holding the original oil filter adaptor to the engine block, I simply tightened all the bolts as tight as can be done with a small 1/4-drive ratchet wrench, and called it a day.
After a few days of driving it, the system altogether seems to not be showing any leaks so far, so that is good. The only thing left to do is to watch all the cuts and abrasions on my wrists and arms begin to heal, since there was no room to get hands and tools up in there easily! No pain, no gain, I guess!
IF anybody else is considering adding this feature to their own late-model Explorer, I can provide you with a complete list of the part numbers, if needed.
