Heater quit working and I can't figure out why need help asap.

[72hemi]

Ok today I drove the challenger up to my parents house (left at 4 am to avoid traffic) and I discovered that my heater isn't working (it was 38F when I got to Redding very cold driving). The blower is still working but for some reason there is no hot air coming out. I read in the 72 service manual that it could be due to low coolant level (which I know my car was low), so I top off the coolant and it still didn't work. When I shut the car off I felt the radiator hose and then felt the heater hoses, and the heater hoses were considerably cooler than the upper radiator hose, if that is a clue for anyone. I have all weekend to diagnose this and resolve it otherwise I won't be able to get to it for at least a month. Thanks in advance.

[73EStroker]

Sounds like thermstat stuck open. If it is at least you got the good one that fails open.

[Chryco Psycho]

 

[71chally416]

Either that or the heater control valve is stuck closed or the wire control cable is bent or came off the control lever.

[Aussie Challenger]

 I would suspect the thermostat, check the temp of the motor though. When you felt the radiator hoses were they "hot" like they should be or just mild hot.
  Another problem if the radiator hoses are "hot" is that the heater core is blocked, because the heater is not on the full flow of the cooling system dirt/rust/scale deposits in the heater core and blocks it just as it can in the radiator. Because we don't use our cars as much as we would like, these deposits settle in the heater. 

[Lunchbox]

Either that or the heater control valve is stuck closed or the wire control cable is bent or came off the control lever.

Wouldn't that only be if he has A/C with a water valve?

Lunch

[72hemi]

Thanks for the advice got it fixed today. Turns out it was the thermostat. It was so weird, the radiator hoses felt like normal operating temperature, but the heater hoses were luke warm at best, I have never seen such a thing. So I replaced the thermostat and disconnected the heater hoses and ran water through them to see if it was plugged and they weren't plugged. Put everything back together and heater works great. And yes only the ac cars have a water valve.

[JS27N0B]

Thanks for the advice got it fixed today. Turns out it was the thermostat. It was so weird, the radiator hoses felt like normal operating temperature, but the heater hoses were luke warm at best, I have never seen such a thing. So I replaced the thermostat and disconnected the heater hoses and ran water through them to see if it was plugged and they weren't plugged. Put everything back together and heater works great. And yes only the ac cars have a water valve.

The temp guage should have been reading lower too if the thermostat was faulty. You may have inadvertantly backflushed the heater core and fixed your problem.