Same issue as everyone else on a 2011 JK. Flushed the heater core both ways with gallons and gallons of water. Let sit with vinegar for a while but everything always came out crystal clear with no change in operation. I finally completed the fix described above, flushed/relpaced the coolant and now everything works like a champ. After I got the old heater core out, some "gunkie" stiff fell out of the return line. I haven't cut it open but I suspect it looks like the photos above. All in all, a fairly easy fix. If I get motivated, I may splice and secure the mounting bracket that had to be cut, but everything seems pretty secure as is.

Thanks

 

I own a 2013 JK with the dreaded cool air on drivers side. I did the heater core swap by way of cutting. I used an oscillating saw on the cuts which made it super easy. It took me about an hour. Next time will be about 15 min.

Note: I only had to cut the lower bracket and was able to pull the upper bracket outward slightly to slide the heater core out keeping the integrity of the upper bracket. I haven't noticed anything negative from doing the cut method. Everything went back together just fine and is very solid.

I had great heat after the replacement but over about 2 months has started getting cool again.

Before the initial replacement I did have sand sitting at the bottom of the overflow tank.

Most recently my water pump went out and when I pulled the water pump I found heavy sand build up in the water pump and in the cavity behind the water pump. Confirming my suspicion of casting sand clogging the HC. (Pics below)

I've owned the jeep four about 8 months and it has 75,000 miles. My guess is this issue has never been dealt with on this Jeep.

I'm actually looking forward to changing the heater core again mostly because I can't stand the thought of that sand being in there. And of course I want heat again.

Thanks to this thread I will be looking into a coolant filter.


Old Water pump

Cavity behind water pump

Cavity after cleanup

 

I did the exact same thing to my 2009. Used C channels and all. Worked out great. Still solid after 2 years. My heater core clogged up at around 70,000 kilometers I think. Not sure if it was casting sand or that I may have mixed the coolant and it clogged it. But now the next heater core swap will be easy. There is a video on Youtube of two guys doing the process. I followed it, pausing at each step and then returning to watch the next step. I too cut the tubes and used heater hose and clamps. Another horrible design by Chrysler. Too bad the engineers do not work on these vehicles. If they did, they sure would improve the design.

 

He used the wrong coolant. Jeeps take a specific OAT coolant with no additives because the system is aluminum.

 

Chiming in for some of the early posts. For those contemplating the HC change and cutting their way in I would do 3 things different. One is use spring loaded hose clamps to hold tension, second is put about a 1-1-1/2" gap where the hoses go to allow flex and the other is to use blue silicone hose not rubber hose. The silicone does not go brittle but does not like rubbing on anything but in this case it is clear of all obstacles.

 

My dealer wants 4k!!

 

I'm in DC region and various dealer quote for oem heater core install was $1,600-$1800 and certified independents with experience on jeep dashboards were $900-$1,200. For sure your $4k quote was a high quote for full system water pump, radiator, etc in addition to core.

 

I agree, mostly. I am contemplating this shortcut. but I think there needs to be a that there can be significant safety risks if not regularly inspected and maintained.

First there is probably an engineering convention or rule against modern cars having any engine cooling system rubber hoses in the passenger compartment side of firewall at all. I googled image searched maybe 100 different model car images of inside dashboards where heater cores are and could see no use of rubber hoses by car makers in last 30 years or so. They may well be forbidden for use, because, unlike a pinhole leak in a hard-line metal house , a blowout of a rubber hose -- in a place where one would normally not inspect anyway -- could cause very serious burns on a passenger. the hose could burst or simply push off due to backpressure -- especially if on a component known to clog.

Also there is no maintenance schedule for inspecting those rubber hoses at heater core, since they do not normally exist. they are not readily inspectable either.

Again, I may myself use the shortcut, I am going to backflush first. But I think people should be aware of the risks, the fact they are not using any barb/bead/ferrule or flaring that is present on all factory and almost all custom interfaceslike this. And that a failure of a rubber hose inside firewall would not just involve a damp carpet inside or a coolant dump on engine side, but a dump of up to 1.5 gallons of boiling water on a passengers legs and major 3rd degree burns. Occurrence risk may be low but consequence risk would be high.

I think the risk should be noted. I also think it would be helpful to discuss best practice on keeping those hoses attached, and reminding people to inspect them at same or shorter intervals than they inspect hoses on the engine side of the firewall.
For sure clamps that self adjust like spring clamps or newer shrink wrap type clamps should be considered instead of worm gear due to large changes in temperature at the joint.

 

As a follow on to my comment, I have been looking at various ways to get a bead on the four tube ends. This method looks like it can be done deftly with the four ends, including the two in situ :