I have this behavior as well, in my 93 F150, with the six. I bought a new thermostat when I first got the truck, and it still did this, so I then sprung for the 'good' 12 dollar thermostat, and it still doesn't get past the N. I'm wondering if it is the guage itself, or possibly the temperature sensor. The heat works, though only in the vent position, due to a missing vacuum hose, and I can't stand it for more than five or ten minutes, even in the 5AM cold.

Didn't move in the summer either.

 

Could be either or both, but mine runs just barely past the N and I'm burning up when it's cranked wide open.

 

Well, I got a proper Motorcraft 192 degree thermostat in her and she's now hitting the "o" in normal. The pressure in the upper hose still seems low, though.

 

How is the heater output now?

 

She heats pretty well. Tough to say for certain, as I wasn't inside very long, and I was just idling in the driveway. I'm still worried that there's not enough pressure in the upper hose.

 

I am using on of the fail safe 195 thermostats, it usually runs on the N or O. Is this really bad? It's in the "normal" range after all!

My fan seems to be spinning full speed even when cold. I can move it by hand with the engine off, but no free wheeling either. I think my fan clutch may need the fluid changed (if they use fluid?) Ever watched a big semi diesel engine run with the hood opened? I saw one yesterday after it had just pulled off the road and the fan wasn't moving at all (40 degrees out) Even in the summer, some are just slowly spinning at idle.

 

Might be an obstruction somewhere. When you flushed, was it inline with the coolant flow, or backwards? I'm trying to think of how to dislodge something that might be restrictiing flow.

It may also be the water pump - the impeller could be damaged or worn. Normally it is the shaft seal that fails on the water pump and you see the weeping from the hole. But changing a water pump can be a PITA, so I would hate for you to do that if it wasn't the problem!

 

I added the flushing tee on the heater core inlet hose, based on what the directions said.

I've never replaced the pump and don't know when it was last done. I know it had a cooling problem prior to my acquiring it, which is why I got a new radiator and hoses. The prior owner also mixed green and orange antifreeze, if that makes a difference

 

Fan clutch is not serviceable. If it is failing, replace it with either a Hayden or Motorcraft. Do you notice any viscous fluid around the shaft of the fan clutch itself? If so, its neared the end of its life. Also, if its failed, it puts a greater amount of load on the pump. Also, if you have flushed the cooling system, you did it some good as mixing the green and the orange can destroy water pump impeller blades.

I would give the truck a good drive and then check to see how it performs. As mentioned earlier, the water pump can be a PITA, and if you decide to go that route, I would clean all of the area around it, and start soaking it with penetrating oil.

 

When I rebuild the motor, it'll get new everything. I have no idea how long the previous owner ran it with orange/green mix. Probably too long. He wasn't a car guy.

I'll check for fluid leakage around the clutch.

 

So is "R" the right temp? I didn't thing the dash Gage was a precision Gage at all, so I didn't worry about it showing n or o since it's still on the normal range.

 

Mine now runs between the O and R. Upper hose is firm. Still, when I rebuild the thing, it'll get a new water pump, but she seems ok for now.

 

Mine runs around the right edge of N, fluctuating to the O, heat is nice and hot, never had an issue. A cold running motor would be over cooled, ie the water pump is fine. The gauge is just a dummy gauge, it basically tells you if the engine is too hot. My upper hose doesn't get rock hard, I can certainly smoosh it even when the truck is warmed up; its only a little more firm than cold.
Doesn't sound like the OP has any serious issue to me. On the cars that I've seen the thermostat stuck open on, the heat is essentially non existent in these colder months and the fuel mileage is ~50% of normal.

 

Wouldn't a soft radiator hose mean a bad radiator cap, since that is what is sealing the system so it builds pressure to raise the boiling point?
I suppose if it never got hot enough to raise the pressure that could be the thermastat...