Have a 2002 Jeep liberty v6 3.7L and the heater blows warm air not hot. I replaced the thermostat and upper and lower hoses and coolent and it still does this. The vehicle is not overheating and the temp guage always sits in the middle or little less. Anybody have a suggestion on where I can check next?
Heater blows warm air not hot
- Thread starter gdlgiii
- Start date
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tjkj2002
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Flush heater core,if that does not work start looking at the blend door in the HVAC box.
first&lastKJ
Full Access Member
My wifes 02 has the same problem, I had to change the radiator due to a leak and I flushed the heator core in the process. It did not help, still blows warm air only.
How would one go about flushing a heater core? I am a little nervous doing that since when I flushed the radiator and dumped the old coolent there was all kinds of stuff in there. Thinking if I did that it could loosen something and possibly crack the heater core? Is this a plausable statement?
How would I get to the "blend door"? The compressor was replaced last week but I think it was doing that before it was replaced.
Checked the radiator and do not see any leaks or any indication of a leak in the radiator (keeping fingers crossed)
Checked the radiator and do not see any leaks or any indication of a leak in the radiator (keeping fingers crossed)
I'd guess the impeller is starting to slip on the water pump. Warm it up, turn heater on full blast at idle. Then hold the revs at 2000 or so, does the air get hotter? Mine did. Also keep in mind, with a new water pump your old radiator may not be up to task and spring a leak like mine did.
ThunderbirdJunkie
Bronze Supporter
ThunderbirdJunkie finds it hilarious that this comes up in the middle of August
The heat blows warm air when heat is on and not hot.
While driving vehicle I would turn it all the way to the right and it blow hot air for about 2 seconds and then blow warm air and nothing else. Accelerating faster does not cause the air to blow hotter.
I rev'd engine to 2000 RPM but still maintains its luke warm temp. The temp guage always stays in middle or little under. The coolent level is a little below the cool level but no sign of any leaks or anything.
Any other ideas? Maybe some sort of vacuume leak behind dash? How hard is it to get to the blend doors to check those out? Does it require removiong the whole dash or can I get to it just behind glove box?
Thanks in advance!
While driving vehicle I would turn it all the way to the right and it blow hot air for about 2 seconds and then blow warm air and nothing else. Accelerating faster does not cause the air to blow hotter.
I rev'd engine to 2000 RPM but still maintains its luke warm temp. The temp guage always stays in middle or little under. The coolent level is a little below the cool level but no sign of any leaks or anything.
Any other ideas? Maybe some sort of vacuume leak behind dash? How hard is it to get to the blend doors to check those out? Does it require removiong the whole dash or can I get to it just behind glove box?
Thanks in advance!
tjkj2002
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The blend door(hot/cold) on a KJ is controlled by a electric motor,the mode doors(vent,defrost,floor) is vacuum operated.
first&lastKJ
Full Access Member
gdlgiii, did you ever get your heater working?
I am still having the same problems as well.
I am at a loss.
I am still having the same problems as well.
I am at a loss.
first&lastKJ
Full Access Member
Tha dash has to be removed to access and check the blend door correct?
Heater problem solved
After taking the jeep back to the mechanic it was determined that the thermostat was the cuprit. I find this interesting because I had replaced it myself back in August. The mechanic gave me back the old one and he told me that it was installed correctly and the right gasket was used so we are both in agreement that I just bought a bad thermostat from Napa.
So now with new thermostat I have heat again.
So lets recap :
Air went out 8 hours after buying Jeep
Replaced A//C compressor (under used car warranty)
Coolent leaking
Water pump bad - had to replace
A/C fan motor only blew 2 speeds - High and Higher. Replaced Blower Fan resistor.
Another mechanic said I had a blown head gasket and when I tested it, it came back negative. Even took it back to the place I bought the Jeep and they tested it and said it was negative. But they gave me a written warranty that if within 6 months the head gasket does blow, they will fix at N/C. Still no white smoke seen from exhaust and oil is clear and not "foamy".
New tires, replaced hoses and I think we have a very good working vehicle!
After taking the jeep back to the mechanic it was determined that the thermostat was the cuprit. I find this interesting because I had replaced it myself back in August. The mechanic gave me back the old one and he told me that it was installed correctly and the right gasket was used so we are both in agreement that I just bought a bad thermostat from Napa.
So now with new thermostat I have heat again.
So lets recap :
Air went out 8 hours after buying Jeep
Replaced A//C compressor (under used car warranty)
Coolent leaking
Water pump bad - had to replace
A/C fan motor only blew 2 speeds - High and Higher. Replaced Blower Fan resistor.
Another mechanic said I had a blown head gasket and when I tested it, it came back negative. Even took it back to the place I bought the Jeep and they tested it and said it was negative. But they gave me a written warranty that if within 6 months the head gasket does blow, they will fix at N/C. Still no white smoke seen from exhaust and oil is clear and not "foamy".
New tires, replaced hoses and I think we have a very good working vehicle!
first&lastKJ
Full Access Member
So your temp. gauge was reading at the proper operating temperature prior to having it replaced?
Yes. From what i observed the temp guage was dead center. After i replaced the hoses (cause they were very swollen wheni bought it) and thermostat, the temp guage would sit just little under middle..now that you got me thinking of this what would happen if i had.a bad thermostat?
TimberWolf
New Member
My 2011 Jeep Liberty doing the same, but opposite, get cold air, no warm. I think I'm going to replace the actuator doors first, and seeing that I have only had the jeep couple of years, going to change rad fluid and reverse flush and change thermostat. Someone was asking how to do flushes, check youtube several great videos. So anyway, someone had some pics on hear oh how to cut by your glove box to get at mode door by hvac. Could some send me that link so i can save them, would be greatly appreciated
![IMG 3817[1]](/data/xfmg/thumbnail/3/3267-d15500e6fbf5fbfa4959b4c33a7612e8.jpg?1623784620)
