swimRubi

I need some help. Could any of you please take temperature reading of your heater outputs on vent and defroster with the recirculation air off? Please have the temp on max heat with the blower on max and after it has been driven at least 3 miles and up to full operating temp. Now I know some of you may be in extreme cold climates so please give the outside air temp (OAT) as well. The OAT where I am has been from 15F to 60F. Yes I do not need full heat at 60F but I was taking readings. I used a digital cooking thermometer.

Here is my situation. I have a 2010 Rubicon with 30K miles now. I had about 25-26K miles on it when the heater out put was ranging from 68deg F to 178 deg F on max heat and max blower. The temp would vary quite a bit from time to time and from vent to vent. The temp would vary from time to time in the same vent. It was generally hotter on the right side and would get colder on the left side. At first I thought it was the blending doors not operating properly. I took it into the dealership (still under warranty) and they found casting sand in the cooling system. Apparently when the engine was casted all the sand had not been removed. It has been to the dealership 4 times now and is still not fixed. They have flushed the system MANY times, replaced the radiator and put in a new short block. Yes a new engine! The thing is they did not do all of it at one time. They flushed it every time, but one time they replaced the radiator and scraped the fine sand off the freeze plugs. I would get it back and put several hundred miles on it and the problem would come back up. Then they replace the heater core. After several hundred more miles the engine was replace and the new radiator flushed. I asked for everything that the antifreeze touched to be replaced at one time. I understand that Chrysler would not allow the dealership to do this. They put an inline screen in the heater return hose just up stream from the thermostat. This thing looks almost like the screen/washer that is in the hose in the back of residential clothes washing machines; however it is a MOPAR part. This screen would plug up with sand all the time. I saw the sand that was pulled out of the cooling system.

I was concerned that the sand was not allowing proper cooling thus allowing the metal to over heat in spots and causing metal fatigue causing catastrophic engine failure. This overheating may not even show up on the temp gauge since it could be over heating in an area away from the sensor.

One other question, does anyone know how the heater core works (and I don’t mean the whole water air heat transfer thing)? In some vehicles the water comes in one inlet on the top and flows through one continuous tube and out the bottom. In the electrical world we would refer to this as series. Do JKs heater cores have a side channel where the water comes in one side and runs through several tubes and out the other side? Again in the electrical world we would refer to this as parallel. This would make since because some of the tubes could get plugged and the air blowing over those partly plugged tubes would be cooler.

Thanks for your help!

yo_marc

That is very very strange.

I'm wondering if that is not casting sand in your cooling system, but your coolant condensating and the protective properties (silicates? phosphates?) falling out of suspension. Using water that's high in iron or minerals will greatly reduce the life of coolant. Not sure if that is something to consider.

I have not looked at the heater core in the JK, but it should operate just like the radiator. Single in, single out, but many parallel passages.

Back in the old days, there was a valve that controlled coolant flow to the heater core. I haven't noticed one like this in the JK, but it could simply have been moved. It was vacuum operated back then, and if it exists today, likely electronically controlled. Perhaps another thing to check...

WhosUrBuddiee

Sounds like a freak occurance. Sorry bud.

jdk

https://www.jk-forum.com/forums/show...ver-side-vents

Looks like you need to compare notes

swimRubi

Thank you for your responce. I can see what you’re saying. Normally I drive back and forth to work which is about 25 miles one way. So the motor is running (most of the time ) 40 min at a time then it cools down. I started having the problem when I took the Jeep on 4 day trip. It was a 12 - 13 hour drive in one day. One day I did very little driving but the following day the Jeep stayed hot (did not have it running all the time ) for 10 ish hrs. I then drove the 12 + hrs back on the 4th day. This would have allowed the chemicals to break down under heat over time. However please look and this picture of the screen that a tech from the dealership is holding.It showes the screen full of “sand”. Does this look like a break down of protective properties or casting sand? The subsance that was removed from the freeze plugs was more like clay.

Thank you again for you time and effort to respond to my posting

Tonka_yellow

To be honest I would drive the piss out of it everyday. If you blow up a few motors they might do something

cg123

My 2010 Jeep is at the dealer right now for a similar heat issue. Cold air on the drivers side and warm air coming out of the other vents. I am optimistic it's just a blender valve type issue but we shall see. Once I have an update from the dealer I will post. What temp should it be blowing at?

DonP

i have had the same problem for 3 yr. It is at the dealership they have had it for 4 weeks
That and my radio keeps frying! chrysler star support was working on it and two engineers and they can not fix it

swimRubi

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swimRubi

I have heard it should be around 170 to 175F. I hope folks here will take temp readings and post them so we all can see where everyone's at on their systems. Thanks for your comment.