So I'm lost.

so here is when she over heats. When I going under 35 mph up hill. Flat land or up hill over that speed she runs cool. Slow walking speed under little load or no load she doesn't over heat. Or even at an idle all day. Just anything under a constant load under 35 she will over heat.
I have just done a complete rad and engine flush New 180 tstat and coolent. Old coolent came out almost clean. Very little brown with no chunks or rust. Both electric fans work great. No leaking coolent nor no water fall noise from heater core. Bleed the system for air with it running with heater on for 30 minutes. No air came out top rad plug. the the only thing I never hear turn on is my clutch fan. When it's cold the fan will only turn maybe a 1/4 turn when pushed by hand. Well I shouldn't say it never turns on because when I start my landi the fan will turn on for about 1 minute or less then turn off. But only when it's cold. If warm will never turn on.

Help

I think clutch fan but I truely don't know

 

clutch fan may have cool air hitting front because rad is obstructed air flow or half full of calcium which wont flush out. when warmed up is rad surface cooler at bottom of fins?

 

paper towel or plastic bag held at grille is sucked toward grille? with and without air conditioning on?

 

they clutch fan only turns on when the truck has been off for a little bit. will not turn on when driving around town or even at an idle for long periods of time. so i am thinking clutch fan is messed up. and there has been only distilled water and antifreeze in the truck. i really don't think any calcium deposits have built up in the truck. only thing that may have happened is it rusted inside a little bit but there was very little discoloration in the antifreeze that came out. i am actually really shocked how clean that antifreeze was.

but to answer your questions yes i piece of paper or bag ill stay on the grill if the truck is running with out the ac on. i tested this when the truck was ice cold and no clutch fan on. i did the same test when the truck was hot after about 30m drive around town and same results.

 

does fan spin more than 1 revolution when tested hot?

 

no it doesn't

 

Dried baked on calcium might not come out so much. Main thing is to test by temperature, if lower rows are cooler then no water going through them.