'04 bare bones Lariat model.
On high, blower is "rushing" the air in the dash yet not very powerful at the vents unless I turn 2 of the 4 off. If its on floor and vent, Very weak but air is still rushing in dash and can be heard under the cowl over the 6.0 regardless of mixer position. No vacuum leaks that I know of and when switching HVAC off you can hear a hiss behind the panel as if air is leaking for a short period of time. Heat temperature isn't that hot either. Right at the vent it is but about 3" out, It isn't. Heater core should not be clogged as I just had the entire cooling system flushed a year ago and maybe 2500 miles ago.

And what is the "normal" warm up time for a stock 6.0? Seems mine takes 30 minutes at either high or low idle and even longer driving. T-Stat is operating as you can see idiot gauge move above thermometer then drop down to halfway point.

Lastly, The temp sensor in my '04 is reading 4-5* higher than the one in my XL 2015 F450. Even sitting side by side. Any idea why this is?

Thanks.

 

Bumpity...