This past weekend I completely flushed the system with a flush product and filled with clean water and drained twice. Then I refilled the entire system with a good 50/50 mix of water/coolant. The heater core is brand new. I just replaced it this past weekend. The clip that holds the cable in place is not slipping... I can see the works clearly as I have removed the glove box to replace the heater core. The thermostat was also replaced this past weekend. That would leave the radiator cap and the water pump that haven't been replaced. I'll pick up a new radiator cap and check that first. All of the hoses look great except for the one that I replaced when I changed the heater core... it wan't plugged up just starting to show it's age and bulging a bit at the hose clamps. So I thought it prudent to replace it at that time.

 

Dont these trucks have 2 temp sensors one for computer and one for guage someone help me here...
I still wonder what temp your engine is and without the guage it may not be warming up to produce HOT heat?? You have checked about everything i would have and sounds like this may be a possible problem. Is it possible to install a aftermarket engine water temp guage just a idea to rule this out???

 

There is 2 sensors. The computer sensor is on the t stat housing and the guage sensor is in the block.. 4.9 6cyl on the back passenger side. I think the 5L and 5.8 in the same place. The
temp of your upper hose should be too hot to hold onto as well. Thess engines tend to run cool but it sounds like there may be a problem with the pump. Im sure there is a way to check the water temp accurately. Pretty sure there is an extra port off the t stat hosing. Mayne thats what its for.

 

I wanted to say thanks to everyone who helped out with suggestions. After several weekends of standing hunched over the engine compartment and under the dash in the cab I have finally got heat back to an acceptable level.

I began by replacing and inspecting the cheapest and easiest items first until I found what the cause was.

Now the old gal (pick-up) has a brand new thermostat and gasket, new heater core, all new hoses (upper and lower radiator, heater hoses, etc) and new water pump. The old pump didn't have the tell tale drip/leak but after changing it out the water circulation improved to a point that all of the hoses were very warm again.

My daughter had her doubts about weather or not I would be able to get things back together again and she did have to carpool with my wife for a week or two.

Somewhere during the course of the truck running sporatically and idling for many minutes trying to warm it up the battery and alternator went dead. Rather than fool around I just replaced them both.

Now we're good to go until the next things breaks.

 

For the $$ you're talkin about to replace stock gauges, good aftermarket digital ones are about the same price.

 

I'm trying to keep it all stock if possible... for now, it's all back together without changing the guage. Maybe another weekend project soon. I'm going to look at the u-pull it places to see if I can find a good used guage for a decent price too.