Heater

[Dixie Dog]

Why does my heater blow cold air while im not moving? When i am moving it blows warm but not real hot.

 

[Jeeper99]

sounds like you're low on Anti-Freeze. When you're sitting still, there's not enough to circulate through the heater core.

 

[JohnnyO]

First check the coolant level as Jeeper99 said. If that's okay, then check the thermostat. It could be stuck, in this case it might be stuck open. What does your Temp gauge read? Last, the water pump could be bad.

There is a very slight chance the heater core could be partially plugged but that's a pretty rare occurrence.

 

[xt master]

:agree:

 

[carnuck]

air trapped in the heater?

 

[SteelHeadz]

Another possibility is a partially plugged up heater core. You can disconnect the heater core hoses and run water from a water hose through it and see what comes out and how much flow you have.

 

[Dixie Dog]

I will check the coolant level. I just drained it bc I had striaght water in there after i replaced the water pump. Wanted to make sure the water pump was working before i put the coolant in.

 

[roadking951]

make sure the vent door is closed mine got stuck open its on the pass side under dash

 

[signgrafix]

All though it was not on my jeep, coolant systems are pretty much the same. I just had this problem on my 94 chevy truck. I had a couple of leaks in the system. One around the thermostat housing, the other in the heater hose. They were dripping on the engine and turbo (hot) so I did not see anything underneath. Once I got all the leaks sealed, I had constant hot air. Also, like the other guys said, once your coolant level gets so low, at low engine speeds it does not puch it through the heating system.

 

[JohnnyO]

There is a very slight chance the heater core could be partially plugged but that's a pretty rare occurrence.

Well.....

I thought ours should be putting out more heat than it was. There was always heat, coolant level was fine, temp gauge is fine, but I thought the air should be hotter. Yesterday I pulled off the heater hoses from the water pump and thermostat housing and flushed the heater core. I have a brass twist-on-off nozzle on the garden hose anyway, which worked perfectly. Stuff it into the heater hose and turn the pressure up gradually. Did it in both directions a couple of times until the water ran clear and a little bit of crud did blow out of it.

Put the hoses back on, drained and flushed the rest of the cooling system with water a couple of times and added fresh antifreeze. The heater air is much hotter now.

 

[carnuck]

Valve hooked to the wrong vacuum port? (only opens under accel)