Hello, I am John, a Ford dealer technician.
I hope I can help solve your problem quickly and accurately.
The only thing you haven't replaced is the fan clutch. This can definately cause your problem. Good job on checking the hc in the coolant bottle, this really helps narrow it down.
If you have any more questions please feel free to ask, it's what I'm here for!
important to me so please leave accurate feedback for others to see my job performance.
I have had very few problems with these engines. One of the few things I have replaced is a couple of fan clutches. I have never seen a blockage in the block on one of these. It would have to be a large blockage to get an overheat because there are pretty large water jackets on both sides of the engine. I think it is very possible that the fan clutch is the problem. Also I don't know if it is possible but make sure the fan isn't on backwards. Another thing to check is if the condenser is blocked with trash, mud or grass seeds. This can also cause overheat problems.