my truck will not blow hot air. no matter how hot the engine is. i got a piece of cardboard in front of the radiator now and the engine temp will get to 190 now but still no heat. i have checked the blend door. took the mechanism off and turned it by hand and you can feel and hear the door move open and close. the temp will go from ice cold to barely luke warm so i am sure it aint a broken blend door. i have checked the heater core. pulled both lines off the HC and ran water on one side and it came out the other side they way it should as far as i know. what do yall think it might be. a guy i go to church with said it might be that the heater core is blocked off, only one tube is letting coolant go through.

i appreciate the help

Eddie

 

If the coolant is comin up to temp and you have circulation assumin the water pump is moving water here the heater core is about the only thing left. Just not much to a heater blowin hot air.

 

our dodges are notorious for this problem if you live outside of southern californa and need your heater your best bet to get the heater to work is check the thermostat start there then work your way to the heatercore now it may be that the vacum lines that run to the air box and control the heat and air controls may have a leak or the pump may be weak thats where id look

 

I've got a write up for this problem...
Heater

But basically the big one are...



Possible locations or causes of obstructed coolant flow:

• Faulty water pump.
• Faulty thermostat.
• Pinched or kinked heater hoses.
• Improper heater hose routing.
• Plugged heater hoses or supply and return ports at the cooling system connections.
• A plugged heater core. (Which is caused by NOT changing your coolant! Just because you coolant is still green or orange doesn't mean its still good.)

Then other menchanic problems...


Possible locations or causes of insufficient heat:

• An obstructed cowl air intake.
• Obstructed heater system outlets.
• A faulty, obstructed or improperly installed blend door.
• A faulty blower system.
• A faulty a/c heater control

As for me... I get roughly about 150*F out of the vents on a cold day...