Over heating when turning A/C on Highway on 1999 Ford Expedition

Flushed Twice, New coolant, New pump, New thermostat 192', New Fan cluch, overheats when A/C is turned on the Highway but not in City traffic What can be the cause of this

2 answers 3 comments
Turn A/C off and the engine runs cooler at hwy speed? And it works fine in town with A/C on? That's bass ackwards! I'm going to guess, radiator restricted or air in cooling system. Who knows? No fan needed at hwy speed!
Well that's what I thought heating up on hwy if A/C is turned on runs fine and does not heat up in city stop and go it runs fine
poss fan clutch is bad. easy to test while eng is running watch fan and have someone turn off eng, fan should stop in about 3-5 seconds.if its goes past that its most likely bad
Found the problem, it was the Radiator being Clogged up
Thanks for all the Help
Glad you found it. Your reply may help others with similar trouble.