Heater not working properly

[Slippry]

For about the past week my heater has been acting up. The car will heat up just fine and the heat works as long as I am giving it throttle. If I come to a stop like a red light I feel the heat coming out of the vents go from hot -warm - then cold. The car is fully warmed up and it doesn't matter how long Ive been driving when it idles it turns cold. If I push on the accelerator it heats back up. Any ideas? Its pretty cold here in Ohio and hopefully this will be a easy fix.

 

[bmrrwolfe]

For about the past week my heater has been acting up. The car will heat up just fine and the heat works as long as I am giving it throttle. If I come to a stop like a red light I feel the heat coming out of the vents go from hot -warm - then cold. The car is fully warmed up and it doesn't matter how long Ive been driving when it idles it turns cold. If I push on the accelerator it heats back up. Any ideas? Its pretty cold here in Ohio and hopefully this will be a easy fix.

Possibly check your coolant level?
Someone will verify this, but atleast its something to start with.

 

[Porkchop]

Sounds like air in the system or low on fluid might want to check for a slow leek in the system

 

[journeyjim]

Does the temp gauge go down when you're sitting at idle? if not it's something in the heating system, a vacuum leak?, I haven't looked at the system to see how it mixes the hot air. When you give it gas can you hear anything behind the dash like a door moving?
If your radiator is low, I think you would be getting a light?
I am really not sure, just throwing ideas out here, I am sure it's any easy fix.

 

[Slippry]

The temp gauge stays the same. Ill listen tomorrow for some kind of strange noise. And Ill also check the coolant in the morning when I have some light.

 

[tjkj2002]

You have a coolant leak,check the radiator side tank,the drivers side top(right by the upper radiator hose) since that is where they crack.

 

[kb0nly]

Sounds like air in the system to me also... Make sure coolant level is correct and your not losing any...

Hmmm.... If your not losing any coolant, not overheating, gauge appears normal at the halfway mark, best guess would be a vacuum problem for the blend door? I don't know, just guess here i would have to look at the FSM. But then if it was a vacuum leak i would also think there would be other signs, like how smooth the engine is running, or even a CEL.

If it was something like a water pump going then you would overheat while sitting idling also. I had that happen once on the POS Neon we had, come to a stop sign and the temp gauge rised and the heat quit due to the decrease in coolant flow.

 

[ThunderbirdJunkie]

For about the past week my heater has been acting up. The car will heat up just fine and the heat works as long as I am giving it throttle. If I come to a stop like a red light I feel the heat coming out of the vents go from hot -warm - then cold. The car is fully warmed up and it doesn't matter how long Ive been driving when it idles it turns cold. If I push on the accelerator it heats back up. Any ideas? Its pretty cold here in Ohio and hopefully this will be a easy fix.

Problem in bold, large font

 

[kb0nly]

I was waiting for TBJ to chime in on that.. Its a Jeep not a Car.... LOL

 

[Slippry]

Yes you are correct it is a Jeep not a car! I'm a little used to saying that because I drove a VW GTI for past 4 years. Anyways sorry I haven't replied sooner went out of town but I am back now. I checked the coolant yesterday and it was extremely low. I bought the car a few months ago and the level was normal. So I filled it back up and the heater is working again. Does anyone know of any good mechanics in Columbus Ohio maybe somebody on this board? My wife also has a 99 Jeep Grand Cherokee and we need something looked at on that as well.

 

[rockymountain]

Hmmm.... If your not losing any coolant, not overheating, gauge appears normal at the halfway mark, best guess would be a vacuum problem for the blend door?

The blend door is electric, so I would rule out any vacuum leak. Best case scenario you are just low on coolant, worst what tjkj said.

 

[Slippry]

You have a coolant leak,check the radiator side tank,the drivers side top(right by the upper radiator hose) since that is where they crack.

I know this topic is quite old but this man was right. There is a crack on the drivers side side tank. My question is how hard is this to repair and what parts will be needed?

 

[tjkj2002]

I know this topic is quite old but this man was right. There is a crack on the drivers side side tank. My question is how hard is this to repair and what parts will be needed?

You need to have a new radiator installed,there is no fixing a plastic tanked radiators.No JB Weld or any other epoxy will not last very long.

Make sure to have only HOAT coolant added after the new radiator.

 

[boebr1]

girlfriends car did the same thing at idle, until I replaced a $5 large fuse in the engine bar that was for cooling fan, then it blew heat at idle. I know it also has a leak because have to keep adding coolant. on this 300M it was a fuse

 

[ddunk80]

Check the coolant level. My 2000 Jeep Cherokee has a constant flow cooling system and the heater will not work if the coolant level is too low.




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[carrobm]

You have a coolant leak,check the radiator side tank,the drivers side top(right by the upper radiator hose) since that is where they crack.

TJKJ, I see that you have listed this on a few different threads. About a year ago the heater stopped working and there was a crack in the radiator. Since then the radiator has been replaced, but the heater still does not work. Do you think there is air trapped in the coolant lines, or is it something else.

 

[Ry' N Jen]

Maybe your heater core is plugged.