Over heating Bronco!

[TexasNomad]

My bronco started over heating yesterday, so I thought time for a new Thermostat.
So new Thermostat new stat housing and did a flush while I was at it.
While idling it will stay cool but as soon as you start driving the temp slowly and steadily will keep rising it take about 15-20 minutes for it to start getting really hot according to the gauge..
I checked for any weeping from the check hole on the water pump and it seems fine coolant looks to be circulating ok, so now i'm out of ideas..
Could be a bad temp sending unit?
Maybe the fan clutch?
Evil Liberal Monkey from hell?
Doc are you sabotaging my Bronco?

 

[m78]

For it to take longer to over heat says its somewhat working. So simple things would be fan belt then fan clutch.

 

[TexasNomad]

The belt is new.

 

[Skandocious]

My first thoughts are either the clutch in the fan (or is it an efan?) or a clogged/dirty radiator. Happened to Rick-- he swapped in an efan and he was talking crap about how it didnt cool his truck enough and he was overheating. Turned out he had CAKED his radiator with mud and air couldn't pass through

 

[surewhynot]

Grab a piece of cardboard and put it in the fan blades while idling. Don't put it in far, just enough to touch the blades. If it stops the fan, the clutch is shot.