2002 Jeep Liberty No Heat.

[MrsBA]

Have replaced water pump and thermostat. Heater core flushed and all lines purged for air. Supply and return lines are hot from heater core. Blend door has been forced to remain open. Outdoor damper closed. Still no heat. FREEZING Please help. What could be wrong? Thank you for allowing me to join and for you looking at my question.

 

[tjkj2002]

Air pocket still or the heater core is plugged.

You can not flush the KJ/KK heater cores,by the design it can not be flushed,do one may open up 10% of the core while leaving the 90% majority still plugged.

 

[Aceofspades]

Is it just a single pass design or dual? Hard to tell from the pictures but trying to understand its design if it's not flushable

 

[MrsBA]

It is a single pass I believe.

 

[Aceofspades]

My 02 has heat. Checked the blend doors. Flushed the coolant. New thermostat and water pump.
But the heat just feels warm until you really been driving a while or the RPMs are increased.

I could use my temp gun and check the temps on both heater lines going into the fire wall see if one is colder then the other.

So in short - your thread catches my attention

 

[tjkj2002]

Is it just a single pass design or dual? Hard to tell from the pictures but trying to understand its design if it's not flushable

You must be registered for see images

My 02 has heat. Checked the blend doors. Flushed the coolant. New thermostat and water pump.
But the heat just feels warm until you really been driving a while or the RPMs are increased.

I could use my temp gun and check the temps on both heater lines going into the fire wall see if one is colder then the other.

So in short - your thread catches my attention

Low coolant level is the number 1 cause of this or a bad water pump impeller but that would lead to overheating at idle(low engine rpm's).

 

[ltd02]

How was the blend door forced to stay open?

 

[HoosierJeeper]

What brand of t stat was used? I'm wondering if it's opening too soon. It's getting warm enough to not trip a rich code and to send the temp gauge to "normal" (which is really a 30 degree range I think) but not warm enough for optimum heat?

 

[tjkj2002]

What brand of t stat was used? I'm wondering if it's opening too soon. It's getting warm enough to not trip a rich code and to send the temp gauge to "normal" (which is really a 30 degree range I think) but not warm enough for optimum heat?

If it was opening early or stuck open it would set code P0128 after 2 failed trips.