Heater problem??

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gdlgiii

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We have a 2002 Sport and having a strange problem with the heater in this Jeep.

The Jeep blows hot air for about 2 seconds then goes to luke warm.
We replaced the water pump (because it was leaking), checked radiator for leaks and no leaks. Replaced T-Stat and flushed and replaced coolant. Replaced hoses.
Replaced the blower resistor because the fan speeds only worked on one speed.

So figure I had all my bases covered but the vehicle still blows no-so-warm air when heat set all the way. When the engine is under a load, it still does not blow hot air. The temp gauge shows normal (just under middle point of gauge)
Any other ideas??
 

Porkchop

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How was it flushed sounds like you have a blocked heater core. Any other signs, like swooshing water under the dash could mean air in the system and needs to be bled proper. If not and fan is blowing the blend air door needs to be checked.
 
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Billwill

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There is a combination of an electrically operated Blend door and vacuum operated doors that direct hot or cold air to the various locations. The most common problem is the vacuum pipe that connects to the intake manifold and goes under the dash has come off or has a leak somewhere.
 

first&lastKJ

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How was it flushed sounds like you have a blocked heater core. Any other signs, like swooshing water under the dash could mean air in the system and needs to be bled proper. If not and fan is blowing the blend air door needs to be checked.

My wifes 02 is doing the same thing. I drove it the other day and I noticed the swooshing water sound comming from under the dash. I replaced the radiator myself.
So what is the proper way to get any trapped air out of the cooling system?
 

first&lastKJ

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There is a combination of an electrically operated Blend door and vacuum operated doors that direct hot or cold air to the various locations. The most common problem is the vacuum pipe that connects to the intake manifold and goes under the dash has come off or has a leak somewhere.

Whats the exact location of this vacuum pipe? I will check that to.
 

Porkchop

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You can burp the radiator by taking the cap off when cold, set the heat to hi start it up and as it warms up you should see the air come out, put the cap back on and drive it for about 20min or till good and hot. Make sure you keep the over flow full before you burp it, after you drive it and aftet it sits and cools off and before driving it again.
 

first&lastKJ

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You can burp the radiator by taking the cap off when cold, set the heat to hi start it up and as it warms up you should see the air come out, put the cap back on and drive it for about 20min or till good and hot. Make sure you keep the over flow full before you burp it, after you drive it and aftet it sits and cools off and before driving it again.

Did this today, still no heat, just luke warm.
Both lines at heater core are hot, so I dont think it's plugged.
 

first&lastKJ

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How do I check the blend door?

I am getting worried that it is the blend door or blend door actuator and the dash will have to come out. That might be a dealer job. Looks like a $600 to $1200 job.


Also with the engine running and heat on hi the AC compressor clutch kept engaging every 10 seconds or so.
Is that normal?
Shouldnt it only be engaged when the air is on?
 

Billwill

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How do I check the blend door?

I am getting worried that it is the blend door or blend door actuator and the dash will have to come out. That might be a dealer job. Looks like a $600 to $1200 job.


Also with the engine running and heat on hi the AC compressor clutch kept engaging every 10 seconds or so.
Is that normal?
Shouldnt it only be engaged when the air is on?

The AC compressor does turn on every so often even with AC off...this is to de-humidify the interior.

I would advise you to download the Service Manual at the link I gave you....cheaper than going to a dealer.:disgust:
 
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