caspershadow

I have a 2000 F150XLT 5.4. The heater **** that you turn to make the air blow hot or cold seemed stiff the other day. Now it seems to only be blowing luke warm air out the vent when turned to full hot. When I turn it back to cold it then blows cold like it should. Anyone know whats going on?

ScrewThat

Check coolant level, check for rust or other potential clogs in coolant passages, check blend door. Has the heater core been replaced?

Personally I'd look at the blend door first.

BlueO2

-make sure the thermostat isnt stuck open
-flush your heater core
-check your water pump, the blades are known to corrode away and the pump will not push enough coolant through the heater core

aside from that list, it may be your blend door. ive never dealt with one, so i cant help you there, but im sure the info's out there if you search for it

caspershadow

I'm not sure if heater core has been replaced I doubt it. I haven't had the truck very long.

MNcamper51

I agree with BlueO2. Most likely the thermostat is opening early

TRD-Toy

If the temp switch turned hard the other day. Maybe the **** on the temp switch broke or cracked allowing to slip on the switch. Seen this before. **** will pulls off easily. Will break by the flat on the ****. Aftermarket does make new *****.

caspershadow

Does the **** simply pull off? I tried pulling gently but it didn't budge. The **** actually feels strange when turning it like it's catching or something.

white89gt

Is your blend door moving correctly? My Expedition would only blow luke warm and it was because the blend door motor had broken teeth. Of course, you should probably hear it trying to move (clicking sound) if that is the issue.

caspershadow

I don't hear anything when turning it from cold to hot or vice versa. I do hear stuff moving when switching from vent to floor and etc.

Tundra Dweller

I changed the stat in my 2000 to a stainless gates with the same temp range.
Much hotter air for heat and more consistent running temp.
Cheap & easy.