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Stock JK TechBulletin board forum regarding issues with OE (original equipment) components of the Jeep JK Wrangler (Rubicon, Sahara, Unlimited and X) such as factory suspension parts, engine, transmission, body parts, interior fixtures and the on-board computer.
Just finished installing a new radiator and heater core (using the shortcut method). My heat is a bit better but still have a temp difference between passenger and driver and the heat changes based on use of skinny pedal. Thoughts?
Skinny pedal variance in heat tends to lean towards you have low coolant/air in the system. Make sure the engine coolant is filled to the top, overflow bottle filled to the max line, and have the system burbed while filling the coolant.
In the mornings you will likely hear a sloshing sound behind the dash when 1st started if the coolant is low as well. If you use remote start, then you obviously won't hear that sound.
Last edited by Rednroll; Mar 11, 2019 at 06:13 PM.
Could my heat be affected by my broken vent circulator (I broke it replacing air filter)? I had the heater core replaced two years ago, and had the system flushed again last year. I am getting warmish air on the drivers side, which I had experienced before I originally had the core replaced. I have yet to measure temps, but that is next on my list. The lack of extreme heat is most noticeable when temps are below 15 degrees. Any insight provided would be great. Thanks!
It's the part at the far right, which is either down or up, depending on if you want air recirculation from inside the vehicle, or air from outside the vehicle. I broke it when I was replacing the cabin air filter, and not it is always 'down' or bringing in air from the outside. I am wondering if this is another factor in the heat temp.
Thanks, not what I had originally envisioned, you probably use the correct technical name, I call that the thinga-ma-jig, connected to the what-cha-ma-call-it with the flapper that controls re-circulate on/off airflow. If the flap is just stuck in the non re-circulate position, I don't believe it will have that much of an impact like you are describing. I took my vent temp measurements with re-circulate off and hardly ever run my heat with re-circulate on, and the temps from my center vents are hot enough to start burning my hands if I hold them close for too long, even in those 7-15deg F temps we've been having.
An odd thing I've noticed which I haven't quite been able to wrap my head around. As mentioned I run my heat with re-circ off. When I crack open my driver's side windows while driving in the cold, and have my right hand in front of the center vent, I can notice the temp of the heat coming from the vent drop down in temp significantly. Then when I close the windows back up it stays at that cooler temp and takes about 1-2minutes before it comes back to full-on hand burning temp. I can't figure that out because it would seem with re-circ set to off, then it wouldn't be sucking in the cool air that is entering the cabin from my open windows.
Last edited by Rednroll; Mar 12, 2019 at 09:41 AM.
Thanks, not what I had originally envisioned, you probably use the correct technical name, I call that the thinga-ma-jig, connected to the what-cha-ma-call-it with the flapper that controls re-circulate on/off airflow. If the flap is just stuck in the non re-circulate position, I don't believe it will have that much of an impact like you are describing. I took my vent temp measurements with re-circulate off and hardly ever run my heat with re-circulate on, and the temps from my center vents are hot enough to start burning my hands if I hold them close for too long, even in those 7-15deg F temps we've been having.
An odd thing I've noticed which I haven't quite been able to wrap my head around. As mentioned I run my heat with re-circ off. When I crack open my driver's side windows while driving in the cold, and have my right hand in front of the center vent, I can notice the temp of the heat coming from the vent drop down in temp significantly. Then when I close the windows back up it stays at that cooler temp and takes about 1-2minutes before it comes back to full-on hand burning temp. I can't figure that out because it would seem with re-circ set to off, then it wouldn't be sucking in the cool air that is entering the cabin from my open windows.
I usually refer to those parts in the same way, but didn't want to confuse anyone. I see you're located in SE Mich, if you ever want to share some insight and wisdom I always appreciate all the help I can get when diagnosing problems with this thing!
I usually refer to those parts in the same way, but didn't want to confuse anyone. I see you're located in SE Mich, if you ever want to share some insight and wisdom I always appreciate all the help I can get when diagnosing problems with this thing!
Your profile says you have a 2012 JK, is that correct?
From what I've read previously on heater core problems, as it relates to getting plugged with engine casting sand, the 2012 and 2013 JK's were 2 of the worst for the amount of casting sand left in the block. First 2 years of the 3.6L...go figure. So if you've had to previously replace the HC due to casting sand, and you have a 2012, that would be my most likely case suspicion....I know sucks. Personally, in knowing that is the case on the 2012s and 2013s, I would highly consider installing a coolant filter system to prevent future heater core blockage occurrences. In your current status, I would start by performing a reverse flush of your HC, since it hasn't been that long since you replaced it and then burb and top off the coolant levels ensuring it is completely full. Then check to see if that fixes your current problems. If it does, then invest in a coolant filter system.
Essentially, what the problem is that you likely have going on is that your engine block has casting sand sitting in it....since someone at FCA didn't do you any favors by properly flushing out the engine block. The coolant gradually picks up the top layer of casting sand and then circulates it through your heater core. The heater core has the smallest passages of the entire coolant system and the casting sand gets trapped inside of it and causing the HC blockages. Replacing the HC fixes the heat related problem, but then the process just happens again if there is still casting sand still sitting in the engine block. What the filter does is that it gets connected between an outlet of your engine block, which feeds the inlet of your HC. So therefore the filter catches that casting sand prior to it making its way to your HC. Thus, you replace a filter instead of a HC until you've eventually purged the entire system of casting sand.
or here is a DIY approach which I've been looking at and will do the same type of thing but at a cost savings.
https://www.amazon.com/dp/B0014BJYYW/?coliid=IQ9ZPUUECGUYP&colid=20TXEAD6EBPRA&psc=0&ref_=lv_ov_lig_dp_it
https://www.amazon.com/WIX-Filters-Coolant-Spin-Filter/dp/B000CSD29Q/ref=pd_bxgy_263_img_2/147-2521075-3382720?_encoding=UTF8&pd_rd_i=B000CSD29Q&pd_rd_r=8a3dfbdb-450d-11e9-af8c-fbca971dfcc1&pd_rd_w=rT5Sz&pd_rd_wg=EaJ1B&pf_rd_p=6725dbd6-9917-451d-beba-16af7874e407&pf_rd_r=9M3ZDEP6BWQ6RJ9TATMW&psc=1&refRID=9M3ZDEP6BWQ6RJ9TATMW
https://www.amazon.com/dp/B000BQPZU8/?coliid=I384XRG6JQ8O33&colid=20TXEAD6EBPRA&psc=0&ref_=lv_ov_lig_dp_it
Lots of different price options of those parts above.
I see you're in Milford. If we can't get you straitened out with some forum troubleshooting, then I work in Novi, live in Warren. We could set up a day where I could bring my pressure tester, laser thermometer, and inspection cam with me to work and stop by after work to assist you with some more trouble shooting diagnosis if needed.
Last edited by Rednroll; Mar 12, 2019 at 02:01 PM.
Your profile says you have a 2012 JK, is that correct?
From what I've read previously on heater core problems, as it relates to getting plugged with engine casting sand, the 2012 and 2013 JK's were 2 of the worst for the amount of casting sand left in the block. First 2 years of the 3.6L...go figure. So if you've had to previously replace the HC due to casting sand, and you have a 2012, that would be my most likely case suspicion....I know sucks. Personally, in knowing that is the case on the 2012s and 2013s, I would highly consider installing a coolant filter system to prevent future heater core blockage occurrences. In your current status, I would start by performing a reverse flush of your HC, since it hasn't been that long since you replaced it and then burb and top off the coolant levels ensuring it is completely full. Then check to see if that fixes your current problems. If it does, then invest in a coolant filter system.
Essentially, what the problem is that you likely have going on is that your engine block has casting sand sitting in it....since someone at FCA didn't do you any favors by properly flushing out the engine block. The coolant gradually picks up the top layer of casting sand and then circulates it through your heater core. The heater core has the smallest passages of the entire coolant system and the casting sand gets trapped inside of it and causing the HC blockages. Replacing the HC fixes the heat related problem, but then the process just happens again if there is still casting sand still sitting in the engine block. What the filter does is that it gets connected between an outlet of your engine block, which feeds the inlet of your HC. So therefore the filter catches that casting sand prior to it making its way to your HC. Thus, you replace a filter instead of a HC until you've eventually purged the entire system of casting sand.
Lots of different price options of those parts above.
I see you're in Milford. If we can't get you straitened out with some forum troubleshooting, then I work in Novi, live in Warren. We could set up a day where I could bring my pressure tester, laser thermometer, and inspection cam with me to work and stop by after work to assist you with some more trouble shooting diagnosis if needed.
That would be awesome! I actually work right around the Novi area! I just can't believe that after a new core and flushes it would need to be replaced again. The part that will be frustrating is that now that temps are rising the lack of heat won't be an issue as the temps in the morning are above 20 so it will blow hotter in those temps.
That would be awesome! I actually work right around the Novi area! I just can't believe that after a new core and flushes it would need to be replaced again. The part that will be frustrating is that now that temps are rising the lack of heat won't be an issue as the temps in the morning are above 20 so it will blow hotter in those temps.
Unless you already have a digital probe thermometer, goto HF and pick up one of those Digital thermometers and take some measurements from the vents and make a note of the outside temp reading. Use the same method as my post #65 I linked earlier.
Turn on about 5 of those thermometer's at HF and pick one of them that is the average reading of the 5. You eliminate getting an inaccurate one that way.
Although, we're finally in the above freezing temps this past week, I'm going to take a guess and say even at non freezing temps the heat from your vents will be below what they should be. You just notice it more when it's colder.
YES! I completed my heater core swap and got everything closed up again.
145degF on the driver side and almost 160 on the passenger side.
The Jeep is toasty warm again. The real test will be when it's 0degF (next winter).
If the flap is just stuck in the non re-circulate position, I don't believe it will have that much of an impact like you are describing. I took my vent temp measurements with re-circulate off and hardly ever run my heat with re-circulate on, and the temps from my center vents are hot enough to start burning my hands if I hold them close for too long, even in those 7-15deg F temps we've been having.
