eater Core questions (yeah as always)

[justjeeps]

So I had my radiator replaced last year and since then the heater core has clogged a few times. Clearly the guy doing the radiator did not flush the system fully or correctly. No problem, pull the hoses, backflush and we have heat.

This year however I again had very little heat the other day, flushed it, felt like good heat but that was with outside temps of 50. Driving over the weekend in temps around 34 it was barely comfortable in the Jeep so I of course assume it just clogged back up.

So I'm flushing again today and nothing came out. I captured all the rinse and there was simply nothing there. Flow appeared good. Should mention prior to that I used a laser temp gun on the hoses and they both came in around 180 if I remember correctly, at the very least there was a marginal difference between them.

So my question is how is the heater core designed? If the core is actually clogged will the water back flushing the system bypass the core and just run along the top like a radiator will? Is the design the same as a radiator or is the Liberty core a solid tube with fins? If I have a good flow going both directions is this proof the core is not clogged or could it be clogged and the water is just bypassing the general core?

Maybe you replaced the thermostat already, if so was it the right temp, did you verify the temp stamped on the thermostat and not just the box?

I have replaced a heater core in my o3 and it was a pita, not to hard but it took a few days and had to make room for all the parts. seats, console, dash, steering wheel and the air bags. It is a big job for a 40 dollar part.

I used the spectra heater core and it does indeed have a different design then the oem. In fact when I was finished the sound coming from the heater core made me think it was leaking big time...but it turned out there must be a valve that did not stay open all the time but would open intermittently and you could here the water flow.

Just be sure you install all the bolts and do not end up with several at the end that got missed...

really the job is not to bad I used a Haynes manual and googled any questions that may have came up. O I did replace my rad a few month prior and then my core went there shortly after..

I know the 02 has old style fan and it is really tight with no room to work. My old 03 was electric fan with lots of room to get at the water pump...have a 02 now and my first thought on the water pump is that will be a pita.

 

[Logan Savage]

I'm having a problem with my 02 . Both heater hoses are hot but air coming out vents is barely warm . Doesn't anyone have an old core that they can saw into & determine once & for all if the coolant can bypass inside the core or not ? I breezed through this thread this time so I'll apologize in advance if this question was definitively answered already .

 

[ltd02]

Is the blend door actuator OK?

http://www.jeepkj.com/forum/f202/how-replace-hvac-blend-door-actuator-59206/

 

[Logan Savage]

I haven't actually checked anything yet except feeling both heater hoses & they're both hot . I'd like a definite answer on the heater core question before I start .

 

[teeje]

Try calibrating the blend door Actuator. With the jeep off put the temp dial to its 12 o clock position. Now turn the key to on. Within 10 seconds of the key being on, do the following sweeps with no longer than 1 second between each one
Full cold
Full hot
Full cold
Full hot
Full cold
Now that that's done, start it up turn it to full hot and see what happens. If need be, remove the glove box and you'll see the blend door Actuator. Have someone help you and have your helper move the temp dial and put your finger on the motor to see if you can feel it moving. You SHOULD be able to hear it. Now, I've pulled my dash 4 times by myself so I can get it out withing 45 minutes maybe less..once to do the heater core which is not fun. So..hopefully it's just the actuator..it IS possible to replace the actuator without taking the dash out..I've done it and so far, I think I'm the only one who has ever done it.

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