A few days ago I noticed my heat was coming out only luke warm when the truck was a operating temp and that it was taking very long for the heat to get to that warm state (~30 mins). I figured I should flush the heater core, and in doing so, I checked my radiator and noticed that the cap was dribbling some coolant out after the truck was shut off. I also noticed the coolant in the radiator was all brown and nasty, so I purchased a new cap, thermostat and a couple of bottles of coolant and water and flushed out the whole system.

By the end of the flush, both the radiator and the heater core were running clear water out. There was definitely some crap in both though. I installed the thermostat and gasket, put the new cap on and got the truck running to temp. I then put the heat on full blast and burped the system. But now, I have absolutely no heat. It's just the fan blowing air out of the vents. Both heater hoses feel cool to me, definitely not hot to the touch like the upper radiator hose is. Also, I noticed when I put the heat and fan on, that i can feel air coming out of the firewall where the heater hoses enter. Is that normal?

How should I go about getting heat back in my truck at this point?

 

Sounds like something in the cooling system is still clogged up. Depending how sludged up the heater core was, it might not be possible to fix it with just a flush. I've seen heater cores that were pretty much solid with crap, the only fix was to replace them.

I would pull the coolant pipe off that connects to the water pump and heater hose and see if it's full of grime. Also maybe the thermostat housing again, since you said the heater hoses feel cool. How old is the water pump?

 

I don't think the core is still clogged, because it was flowing real good with nice clean water by the end of the flush. I already checked the hose that connects to the water pump and it looked pretty clean. The thermostat housing was nasty, but I cleaned it all up very well when I replaced the thermostat.

I've never replaced the water pump and I bought the truck 6 years ago... I'm assuming it's either original or very old.