What things do I need to look at to address low heat temperature?

TX99517

TX99517

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I did a search and abunch of threads come up that don't have what I'm looking for, or I'm doing the search wrong.

Aside from flushing the heater core, what things do I need to look at to address the low heat temperature?

Things I Know:
1. I hear the blend doors moving. They move from floor, dash, and defrost.
2. Heater blower works, well.
3. On/off works.
4. temp knob works I think as when I put it to cold, the ice cold air comes in. When moved to hot, it's warmish around 80 F coming out the vents.

I have been driving it the last two weeks to work and it has been moderatly comfortable in single digit to teen temps. Today, was sitting around 0 outside and it was miserable. No warm air at all, and my fingers are still numb. Took it to get lunch and had the same moderately warm air coming out as before, but the temp is now in the teens.

I get these things are the best with heat, just trying to get some consistency.

Thanks
 
Rubicon88 said:
These things are actually schorchers if working proper.

Coolant level/leak since you said it "was" ok...
If you're low it won't blow hot enough.

Your heater core....very important.

Water pump...

Engine temp is?
Click to expand...
New radiator and fluid last month with new 195 thermostat and radiator cap.

It's too cold still to flush the heater core, maybe next month when it stays in the 40's.
Temp gauge holds between 200-210 since replacing the radiator and thermostat.

Haven't had a chance to use the scanner yet. Not sure what I'm looking for on that for temp.

Water pump, I have not done. E
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I have no clue what all that means. Just got home and this is after driving 15 miles at highway speed.
 
ECT (Engine Coolant Temperature) is what you're looking for on the OBDii scanner. I see a 190 and a 199 in your pics, which should be able to generate sufficient cabin heat. How do the hoses to/from the heater core feel?
 
rouxbicon said:
ECT (Engine Coolant Temperature) is what you're looking for on the OBDii scanner. I see a 190 and a 199 in your pics, which should be able to generate sufficient cabin heat. How do the hoses to/from the heater core feel?
Click to expand...
The top one is hot and the lower one is less hot.
Easiest way to explain
 
That’s what I figured. I’m hoping a good flush with solve it. I am going to at some point check all under dash stuff as well.
 
With a correctly functioning cooling system, ECT should show 210 once warmed up and should then stay pretty close to that temp.
 
RMETeeJay said:
With a correctly functioning cooling system, ECT should show 210 once warmed up and should then stay pretty close to that temp.
Click to expand...
It is normal for the actual ECT via OBDii reader to vary more than the needle on the gauge is programmed to indicate, so I wouldn't be alarmed by a 199 deg OBDii reading, especially in 0 deg ambient temps. It is true that the thermostat should hold it at a more-or-less stable temperature, but it won't be a perfectly flat line graph.
 
According to my OBD the temp ranges from a low of 192 to a high of 206 typically cycling in the high 190's.
The gauge stays between the 2 and .
I would consider 190-199 in the normal range.
 
If my ECT wasn’t showing 200-220 range with an average of 210 during normal driving, I would consider that a problem. With properly functioning O2 sensors, optimal combustion takes place within those temperatures and will help the 4.0 have the longest lifespan possible.

Back on topic, it’s not clear what conditions the data were captured in. If done fully warmed up, I would suspect a lazy thermostat or malfunctioning fan clutch.
 
I've had weak heat in my TJ since I got it. 195 thermostat replaced twice, coolant flush, no leaks, etc etc. I've been smelling a little coolant recently inside the cabin so I decided to replace the heater core.

When I split the box I found like half a cubic foot of shredded paper, straw, bits of leaves packed in around the bottom of the core & condenser. At some point this thing must have sat & become a long-term residence for a rodent. About the bottom 1/3rd of my heater core was completely packed with a nest.
 
Rubicon88 said:
Not really...

These Jeeps when fully warned seem to bounce from 197 - 202,3 or 4

They don't just sit there at 210 all day.

I'm talking real time data to the 10th degree.
Click to expand...
This is consistent with what I saw after flushing the system.
 
N757KF said:
This is consistent with what I saw after flushing the system.
Click to expand...
Perhaps looking at a gauge and I won't say none run at 210.... but I can tell you from watching real time data on many of these...If it's in and or around 200 degrees it's good to go.

Run them hard you'll see 204...maybe 206...
Back off some and you'll see 197, 198, 201...

These are not the most highly scientific machines for sure.

The problem here is he's getting the right heat at the engine but not enough heat out the ducting.

Heater core, under the dash, or water pump. Coolant low as well?
That is the issue.
 
Rubicon88 said:
Perhaps looking at a gauge and I won't say none run at 210.... but I can tell you from watching real time data on many of these...If it's in and or around 200 degrees it's good to go.

Run them hard you'll see 204...maybe 206...
Back off some and you'll see 197, 198, 201...

These are not the most highly scientific machines for sure.

The problem here is he's getting the right heat at the engine but not enough heat out the ducting.

Heater core, under the dash, or water pump. Coolant low as well?
That is the issue.
Click to expand...
Agreed
 
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