I installed a engine block heater in my 07 Expedition today. I thought I would go through the procedure to make it faster for the next person that does it to their 07 Expedition. I bought a Kat's engine block heater that installs in a freeze plug hole on the engine from Checker auto parts $17.50. Since there is really only one location to mount it and access it, I chose the left rear freeze plug on the 5.4. As you can expect like most things on todays cars, you can see the plug very well but can't get more than one hand in the work area. The first thing is to drain the radiator. The drain is on the right side rear of the radiator and kind of hard to get to. I had to go to the hardware store and get some 3/8 plastic tubing to go over over the plastic drain valve as FORD did not include a drain tube. Total cost for the drain tube 72 cents. So Using a clean bucket I opened the valve with a screwdriver only to find that I can see why there is no drain tube. The coolant just sprays out the end of the drain valve as well as out the drain tube. (great design here). When the radiator was drained I noticed that the engine was lower than the radiator so I was sure that the engine had more coolant that need to be removed. I could find no drain valve on the engine, but there was a allen wrench type drain plug below the soft plug but I don't know how hard it would be to get out as it looked like it was really tight. So the front drive shaft was in the way and I used a long screwdriver and hammer to drive the plug out. I had a bucket handy to catch the flood.
Five good whacks with a big hammer and yep a flood. After the flood the soft plug was spun around so I could pull it out with channel locks.

Now for the heater installation. The heater instructions said not to use any sealant but I used some hi temp silicone anyway around the O ring. The heater is held in with a toggel bolt arrangement. A allen wrench tightens the toggle wings. This was a real trick doing this with one hand as the heater wanted to spin in the hole. The instructions did not say which way the heating element should point so I pointed it up as it seemed to be a clear area inside the block. Finally got it tightened up, don't over tighten. Connect the cord routed it through the motor mount and tie wraped the plug to the pull hook on the left side. Closed the radiator valve, filled the radiator tank, started the engine, waited for the thermostat to open and then checked the tank for the proper level. Checked for leaks. None found. Plugged in the heater, seems to heat. Cleaned up the mess (and me too). And that was It. I may have left something out but that was about it.