I am having heater problems with 2008 Nitro.

Last winter, the heat worked fine. Now, it just blows cool air. Not as cold as the outside air, but not warm at all.

Here's what I've tried:

The coolant tank is full. The hoses running to and from the heater core are hot. I flushed the heater core. I took off the blend door actuator and it seems to operate properly when I change the temp control.

The next step I took was to manually turn the blend door gear. The air temp did not change. Then I took off the actuator that changes the air flow and the 3 gear pieces plus the large plastic plate behind it. Next, I manually turned the three gears that adjust the blend door and air flow direction. This is where I get stumped. 2 or 3 times, I got hot air to come out of the defroster. I could not replicate that on demand. There seemed to be no rhyme or reason as to when I got heat. Most of the time, the air was cold or mild. No only can I not duplicate reliably to fix it, I have no idea how to align the gears that I took off to even put it all back together again.

So, I need help understanding my next step and I need a diagram detailing how to put gears back into proper alignment.

/sigh

 

In the last couple months have had a issue of losing heat. Temp gauge comes up just fine to normal operating temp, coolant level if full, new thermostat. the nitro will produce heat about 1000rpms, if you let it set idling then you lose the heat. any suggestions would be appreciated.

 

hey guys. I've been struggling with this for months. I tried EVERYTHING I had found on forums without replacing the heater core. Well now my heat is running me out of the car. So good that in -0 temp I can drive 70 with my window down and still be hot. So here is what I've done but first a few signs that this might be your problem as well. Get your car up to temp. Turn the heat on but the fan on low. Turn everything off that would make noise or just put it in park and rev the engine a little, listen for gurgling coming from behind your dash. Also your heat may improve at higher rpm. I was having a load of problems with mine so many that I had just about gave up trying to trouble shoot the cause. Heat on passenger but not driver side. Cold air on drivers floor. It was weird. Sometimes it would work in certain areas sometimes it wouldn't. Anyway. What I did is this. First I took off my heater core houses and put them back on in reverse. I'm not sure if this could damage anything but so far going on over a week and everything is completely fine with mine I will probably switch them back around sometime soon. But I did that and left my radiator cap off (ENGINE HAD COOLED DOWN PRIOR TO THIS) I reved it up a bit to about 2000 rpm or so letting off and on and just watched in amazement as everything nasty came flowing out the radiator. I had flushed it several times before using the water hose method. Ok, so did that for a min or so till the coolant looked somewhat normal then and this I think might be more important than that and is where the gurgling comes from. I secured a funnel TIGHT into the radiator so it would not leak coolant. Then added slowly until the fluid level was about half way up the funnel. MUST BE significantly higher than the rest of the cooling system. Your car needs to be up to temp for this. Do that and rev till about 1500 rpm or so and hold it till the thermostat opens or the rad fan kicks in then let off and fill it up again to about the same distance up the funnel. Set out there with it and just watch all the air start coming out the funnel and fill as needed keeping it higher than the rest of the system. Wait for the fans to kick in again or thermostat open then add again. Do that about 3 times maybe squeeze the upper rad hose until the level doesn't drop anymore and then put your cap back on and enjoy that piping hot heat. I am not a mechanic as you can probably tell by this post but just really wanted to help someone with the problem I was having after months of troubleshooting. I sincerely hope that this helps someone. Also if while your cap is off and your holding rpm to reach temp and coolant is shooting out of your radiator cap with some force not just running over than you're probably looking at a bad thermostat too. I had already changed mine though so did not encounter that. Really hope this helps and if any mechanics would like to turn this post into a better worded more informative post that is fine with me this is just the best I can do. thanks you'll and good luck.

 

This seems to be a common problem and I can't seem to figure it out. It doesn't blow super hot, maybe Luke warm. Coolant levels are fine and I just had my thermostat replaced. I bought this from a used car lot and took it back to them to have the heater core line flushed. If they did it correctly I don't know. I had this done before I replaced the thermostat, because about a week after the malfunction light came on and the code that came up was basically mine was stuck open. I was hoping that would have fixed it, but it didnt

 

This seems to be a common problem and I can't seem to figure it out. It doesn't blow super hot, maybe Luke warm. Coolant levels are fine and I just had my thermostat replaced. I bought this from a used car lot and took it back to them to have the heater core line flushed. If they did it correctly I don't know. I had this done before I replaced the thermostat, because about a week after the malfunction light came on and the code that came up was basically mine was stuck open. I was hoping that would have fixed it, but it didn't. I don't know what to do, on really cold days I can't put my kids in the car where I can't keep them warm. I have had a heater core go out on a 93 blazer years ago and I remember there was a smell of antifreeze and the cabin would fill up with the mist. Any ideas for a single mom not wanting to get ripped off by a mechanic?

 

Maybe water pump or blend doors. Hard to tell.