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Author Topic: no heat  (Read 3353 times)

Offline OJTV8CJ

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Re: no heat
« Reply #15 on: 01/ 6/10 - 01:19PM »
You use vinegar to remove any hard water scale, as vinegar will disolve it.  It is the main reason for not using tap water in cooling systems, as all manufactureres require you to use distilled water. 

I have never heard of using Dawn, but I agree with Steve and would use vinegar.

Cap the bottom of the heater core and fill it with vinegar, let it sit and flush it.  Do that a couple of times and you should be able to get any scale out of the heater core.

You DON'T want to pull the heater core.  It is about a 6 hour job.  Also, make sure that there isn't any gates or valves in the heater core lines.  On some of the older Jeeps, not sure about the new ones, that had an isolation valve that opened when the heater was selected to isolate any heat sink thru the heater core in summer months.  This could be stuck shut, and is eliminating the ability of the antifreeze to heat the heater core.

You should be able to wrap your hand around the heater hose when the Jeep is up to temperature to see if it is getting to the heater core.  Check both lines.  If one is significantly cooler than the other then it is a flow problem thru the heater core, if both are cold - then it could be the outlet at the water pump, thermostat, or the isolation valve that I was talking about before.

Let us know. 
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Offline TJ-2thousand

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Re: no heat
« Reply #16 on: 01/ 6/10 - 01:52PM »
Ok. So the top was hot and the bottom hose was just a little warm.
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Offline LoneWolf

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Re: no heat
« Reply #17 on: 01/ 6/10 - 03:07PM »
simply diluting your antifreeze to 50/50 might solve your problem too. Undiluted antifreeze is thicker and doesn't work itself through the engine like it needs to. Everyone thinks it's better to use straight antifreeze, but it's not.
if you do, mix it before you pour it into the radiator.
good luck.
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Offline xj42

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Re: no heat
« Reply #18 on: 01/ 6/10 - 03:17PM »
Quote from: LoneWolf on 01/ 6/10 - 03:07PM
Undiluted antifreeze is thicker and doesn't work itself through the engine like it needs to. Everyone thinks it's better to use straight antifreeze, but it's not.

I don't know about this statement.  Antifreeze will get everywhere water will, its heat transfer properties aren't as good, compared to water.
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Offline freds_94

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Re: no heat
« Reply #19 on: 01/ 6/10 - 03:22PM »
i put vinegar in my dogs water bowl every morning    ::)
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Offline LoneWolf

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Re: no heat
« Reply #20 on: 01/ 6/10 - 03:24PM »
I stand by my statement.
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Offline TJ-2thousand

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Re: no heat
« Reply #21 on: 01/ 6/10 - 08:25PM »
Out of curiosity, why is it such a hard job to remove the heater core? Does the whole dash have to come off?
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Offline OJTV8CJ

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Re: no heat
« Reply #22 on: 01/ 7/10 - 11:21AM »
Quote from: TJ-2thousand on 01/ 6/10 - 08:25PM
Out of curiosity, why is it such a hard job to remove the heater core? Does the whole dash have to come off?

Yes.

You have to remove the whole heater assy which requires pulling the whole thing out.  Unless they changed something on the TJ's.  On the older ones it is a giant PITA.

Where you see the barb's for the heater hoses, that is where it is on the inside.  So look on the inside and determine if it is worth it.  Or call a shop and ask them how much it will cost to replace it and see what the hours would be.
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Offline LibertyPatriot

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Re: no heat
« Reply #23 on: 01/20/10 - 11:13AM »
Did you get your heat working?
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Offline TJ-2thousand

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Re: no heat
« Reply #24 on: 01/20/10 - 11:57AM »
no. after it warmed up, i forgot all about it. i plan on working on it today.
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Offline TJ-2thousand

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Re: no heat
« Reply #25 on: 01/20/10 - 12:27PM »
my cap gets hot. the tstat is working properly. the temp gauge will go up to 210, then the stat opens then goes down to 180. the top hose to the core gets hot but the bottom hose barely gets warm.

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Offline LoneWolf

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Re: no heat
« Reply #26 on: 01/20/10 - 12:39PM »
sounds like it is working as it should... must be the core.
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Offline LibertyPatriot

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Re: no heat
« Reply #27 on: 01/20/10 - 12:48PM »
Yeah, sounds like the core is plugged up.
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Offline xj42

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Re: no heat
« Reply #28 on: 01/20/10 - 12:57PM »
Quote from: LibertyPatriot on 01/20/10 - 12:17PM
I was just curious.
Does your radiator cap ever get hot?
If the tstat isn't working and you have a coolant leak into the engine and burn off what's in the block but the tstat won't open to let coolant from the radiator to flow to the block then you won't have enough coolant to flow into the heater core.  I think that's what was happening to mine.  The tstat doesn't work well and when I finally got enough coolant into the block/heater core mine started blowing hot air.  I picked up a new tstat but haven't installed it yet.

After reading about the 2000 model year heads cracking now I'm worried about the one I just bought.  There is a certain head casting that is prone to cracking.  I don't remember the casting number, but a Google search will bring it up.  I haven't checked mine yet to see what the casting number is.

0331 I believe, I have one too.
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