this may not be news to everyone but i have not seen it befor.
i have just spent two months chasing a barely overheating 4.7L in my 2001 dakota.
flushing, radiator cleaning, thermostat, rad cap, check electric fan all checked,cleaned, fixed or replaced, but when i climb the mountain 2000 feet vertical in 7 winding miles, the engine starts to boil, soon i am in the red zone!?!?!
out on the freeway i am hot but not concerned, apparently the air flow is enough.
in stop and go with AC on, i am going to boil just as climbing the mountain.
it has turned out to be a wasted viscous clutch on the mechanical radiator fan.
sure, the fan always spins but is it doing any work???
to test, 1.) make sure your engine is hot because this locks the viscous clutch. 2.)open the hood and observe the fan 3.)go turn off the engine while observing the fan. 4.) the fan should stop with the engine and NOT keep spinning. The bad clutch spun 20 or so revolutions, the new one didn't even free spin 2 times.
when i went to buy the clutch($130) at the dealer the parts man said that dodge's data base indicates dodge sells 326 viscous clutches with my part number PER WEEK in the 50 states!!!!! WHOLEY GUACAMOLEY!!! 326 PER WEEK??
i am not sure how to link this in order to get better coverage to other forums but please do it for me if you can.
i am just glad to finally get this nagging problem fixed.
Good Luck from Colorado

 

Do you mean the fan clutch that attaches with the fan to the water pump? I'm seeing a similar issue and so far one of the last few things I haven't done is replace the fan clutch and have the radiator totally cleaned out. I have a 2000 Dakota (5.9L). Thanks!

 

Are you sure your water pump is working?

 

a lot of people get rid of their clutch fan totally. most of them go with the electri one from moes performance. a flex lite black magic 180 for 240.00. or you can get rid of the clutch style fan and get a direct bolt on from flex lite