Lack of heat in an '03

[Kingfish]

Howdy All,

I have an '03 Sport V6 with 110k miles that's not putting out much heat. (which ***** because it's cold in CT right now) I filled the overflow to the max cold level thinking it might have been low, and let it run up to op temp but the heat was only blowing warmish air. If it's not a coolant issue could it be a heater blend door or something similar?

 

[CzarKJ]

Few options. Blend door actuator. Clogged heater core. Few more but you would see other symptoms (T-stat or waterpump issues). What coolant did you use?

 

[Aceofspades]

Does it seem to heat up more when you have the dial on the first setting ?

 

[Kingfish]

Few options. Blend door actuator. Clogged heater core. Few more but you would see other symptoms (T-stat or waterpump issues). What coolant did you use?

Zerex pre-mix for Chrysler vehicles. (no phosphates)

 

[Kingfish]

Does it seem to heat up more when you have the dial on the first setting ?

Dial on the first setting? I don't understand.

 

[wbw]

Dial on the first setting? I don't understand.

I would like to know also. I have the same problem. Warm air, not hot, and it doesn't blow out of the drivers side foot well. I haven't used the Jeep much lately.

 

[tommudd]

Thermostat
Clogged heater core
Low coolant
Water pump

First things to check
How much coolant did you have to pour in to bring back up to proper level?

 

[Aceofspades]

Dial on the first setting? I don't understand.

Yup
I did all of things on the list by Tom and I noticed recently the heat much hotter on the setting for the recirculated air aka the first dial setting - shows a jeep icon with the snow flake.

 

[M38 Bob]

What's the in dash temp gauge showing? If system's full and gauge reads 1/2 there should be heat, so probably a core problem. If gauge reads low, then coolant's not reaching op temp, meaning likely thermostat issue.

 

[M38 Bob]

Yup
" - shows a jeep icon with the snow flake."

OMG!!! A Democrat Jeep!!! :happy175::happy175:

 

[tommudd]

Not Jeep KJ related

 

[M38 Bob]

Not Jeep KJ related

Just can't pass on the low hanging fruit.:gr_grin:

 

[TheRealG]

Sounds like the Heater Core. I just had mine replaced on my 2003 with 148K miles, and my symptoms were almost identical. It's a whole big process unfortunately. Not cheap either. I took it somewhere because while I have the know-how, I didn't have the time to have the dash torn apart for several days.

 

[jeepop]

There is a good youtube video about how to flush the heater core. Put a trash bag over the fuel injectors and ignition coils first.

Flushing the heater core fixed ours. It will melt the wool on your toes now.

 

[Kingfish]

There is a good youtube video about how to flush the heater core. Put a trash bag over the fuel injectors and ignition coils first.

Flushing the heater core fixed ours. It will melt the wool on your toes now.

I just recalled, a year ago or so we had a leak on the radiator where the lower hose joined so the rad was replaced. The coolant was *nasty* and looked like it hadn't been replaced ever. I'm willing to bet a heater core flush might fix the issue. I found the YT video and will take a shot at it Friday when I'm off.

 

[Kingfish]

Is there anything out there that I can use as a mild solvent to help flush whatever crap is living in the heater core out? What's not harmful to aluminum? Or should I just stick to hot water?

 

[Aceofspades]

There’s a prestone kit I’ve used to add access ports to heater lines on my other vehicle to flush and clean the whole system. The cleaner included was decent. You decide if you want to flush the system or just the core - if just the core I couldn’t think of way to recirculate the cleaner without getting fancy.

 

[Winka]

Hi all yes I'm a newbie but I have the same problem with my KJ ie lack of heat I will watch this thread with interest as I'm in the UK its always bloody cold .

 

[tjkj2002]

There is a good youtube video about how to flush the heater core. Put a trash bag over the fuel injectors and ignition coils first.

Flushing the heater core fixed ours. It will melt the wool on your toes now.

I just recalled, a year ago or so we had a leak on the radiator where the lower hose joined so the rad was replaced. The coolant was *nasty* and looked like it hadn't been replaced ever. I'm willing to bet a heater core flush might fix the issue. I found the YT video and will take a shot at it Friday when I'm off.

Is there anything out there that I can use as a mild solvent to help flush whatever crap is living in the heater core out? What's not harmful to aluminum? Or should I just stick to hot water?

By design you can not "flush" the KJ's heater core,you may get 10% open and a temp fix at best.

 

[jeepop]

I've read that now a coulee of times .... but .... I started with my hose pushing water through one direction. The water flowed through ok. I reversed direction. It flowed through ok. I reversed direction again and a glob of pink snot looking mucus came out and the water flowed through better. Now we have full heat. So regardless of design something flushed out, maybe it was just crap in the tubes that go to the core versus in the core itself but it worked.


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