No heat in cab

T

TJforLife

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tennessee
Hey guys I know this question has came up alot and I've read alot of posts and I still haven't found the answer.
So there's no heat at all in the cab. Blower works fine. Blows strong thru all vents, floor, and defrost.
We noticed this when we first got jeep last spring. Then I flushed heater core and check door actuator. Still didn't help so I just left it. Now it's getting colder outside so I'm back at it again.
So the hoses going to heater core are getting hot. Both of them. Blower motor is working fine. Thermostat is getting jeep up close to 210 in a very short period of time. Hose going from radiator to Thermostat gets really warm also after engine warms up. The previous owner installed new water pump, radiator and Thermostat before we got jeep. Because of this I thought maybe air in the lines. So today i jacked up front of jeep and squeezed the top hose multiple times. So air bubbles did come out and I would continue to refill as needed. I did this while engine was cool, then continued even after it reached 210 degrees. Continued util no more bubbles.
Also took door actuator off today and checked it. It turns full directions. U can turn door by hand with actuator off. So alls good there.
There isn't any leaks in the system that I can tell. Since the flushing of heater core last spring we haven't messed with coolant till today. Which has been about 8 or 9 months. Today I had to put in about a pint of coolant before I started the burping process. Over flow tank is at the full mark. It didn't need any fluid. With all that we still aren't getting any heat. Does anyone have anymore ideas that might help
 
Well let me ask this question. If I have flushed heater core and I currently have 2 hot hoses coming out of heater core could the heater core still be bad? If so please explain
 
TJforLife said:
Well let me ask this question. If I have flushed heater core and I currently have 2 hot hoses coming out of heater core could the heater core still be bad? If so please explain
Click to expand...
Given that information a bad heater core doesn't seem likely if flushing produced good water flow/volume in both directions.
 
If I remember correctly, the heater core inlet/outlet are connected to the same tank. The internal tubes could be clogged, forcing water from inlet to outlet without flowing through these tubes.
 
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I wonder if you disconnect the heater hoses...or at least the top one from the firewall and run a borescope in the tube what would you see?

I bought one on Amazon for $30 and I think some auto parts stores loan them out.

If you pinch off the hose you wouldn't loose too much coolant... although you might not see much until you drain the heater core...I wonder if there is any efficacy to measuring the amount of coolant that comes out...hmm.

-Mac
 
Couldn't hurt to check the direction of coolant flow.

Heater Hoses.JPG
 
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John Cooper said:
I would flush and also reverse flush it, the core could be stopped up in the middle and the water is just going around one side or the other.
Click to expand...

So I reflushed heater core today. Both directions. We are now getting some heat but not very warm. So I'm guessing it is a partially clogged core. I sure didn't wanna tackle that replacement! Thanks for yalls advice
 
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TJforLife said:
So I reflushed heater core today. Both directions. We are now getting some heat but not very warm. So I'm guessing it is a partially clogged core. I sure didn't wanna tackle that replacement! Thanks for yalls advice
Click to expand...

I had to do this to mine after sever years with no heat (not a DD). After one or two flushes, I got traces of heat. I ended up doing it 5-6 times and it was hot as hell! I don’t exactly remember the process, but I did let some chemical sit overnight during the 4th or 5th flush. Keep at it!
 
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What heater core does the vehicle have? if you have that info... Could be a bad heater core. Had spectra in mine that with the hot coolant, at running temp, going through the core produced little to no heat.

edit: heater core is not "bad" but does not have the fins to be able to heat the air as it passes through!
 
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Morks said:
What heater core does the vehicle have? if you have that info... Could be a bad heater core. Had spectra in mine that with the hot coolant, at running temp, going through the core produced little to no heat.

edit: heater core is not "bad" but does not have the fins to be able to heat the air as it passes through!
Click to expand...

That was my first thought also. With all the reports of "new" heater cores with lowsy output, it can't hurt to pose the question.
 
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Nashvillwill said:
I had to do this to mine after sever years with no heat (not a DD). After one or two flushes, I got traces of heat. I ended up doing it 5-6 times and it was hot as hell! I don’t exactly remember the process, but I did let some chemical sit overnight during the 4th or 5th flush. Keep at it!
Click to expand...

Am having a hard time picturing how to do this as I have the same issues as OP.

I’m assuming you disconnect the hoses running into the firewall
Then you ad some chemical into the heater core until it’s spitting out on both ends. At that point you stop and just let it sit in there over night?

What would be a go to chemical
 
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Any type of Radiator flush.

Do not use the CLR stuff it eats aluminum up from what I understand, plainly say on the bottle not for aluminum.
 
Do you have good airflow out of your vents and defrost, can you check the air temp out of the vents with the temp control in the cold and hot positions to see if there is any noticeable difference??
 
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