Heater core back-flush fixed heat on 2011

Hogges said:

I was about to hack into the dash to install a new heater core, as per the many YouTube videos illustrating how to do it. But I tried a back flush of the heater core first, combined with all new coolant. I used a combination of water from the garden hose and my air compressor, alternating between the two. I flushed in both directions but started from the back side, hoping to clear jammed debris in this way.
It worked! There is still a little bit less heat on the far left vent compared to the others, but a far cry from the ice cold air we had before. I am glad that I tried this less invasive method first.

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Good job @Hogges ! Sometimes it pays to try to simple fix first!!

Before I drop the Hemi in for the final time, I'm absolutely going to do this...

I actually took a measurement of the heatcore hose (16mm btw) so I can get some clear tubing. My plan is to use some CLR to help dissolve any sediments that have built up in there, then use water and compressed air to "flush" it out like you mentioned.

Hogges said:

There are tools dedicated to coolant flushing. Some look like pressure washer guns, where you hook up the water hose to one terminal and the air compressor to another. Since none of these was available for purchase locally and I needed to take advantage of the one day above freezing, I simply stuck the brass sprayer end of the water hose into the heater hose and then alternated with my air compressor blow gun, which also fit pretty well with the hose inside diameter. If I had to do it again, I might spend the $35 or so for one of these in hopes of getting an even more thorough flush.
My daughter used the Jeep in the past few days with temperatures around 10F and reports that her heat works great.

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Interesting - can't say I've seen them before. I had noted a forum or maybe a Facebook post from a while ago where someone mentioned that they did exactly as I described above (using CLR to dissolve and then use air/water to flush everything out). Two people in that same thread said they did the same and they have perfectly functioning heat.

Those "flushing guns" look fairly straight foward. Here's the one I found on Summit Racing: https://www.summitracing.com/parts/...pLD2ypwwimuNDTS2SHpgDOVnabY5QiewaAmRhEALw_wcB

I may order this and have it ready, since I have the Jeep in the garage and a hot water hose connection nearby...

I went ahead and ordered the Lisle one from Summit... should be here mid week. I'm going to try to pick up some clear hose (just to visually see what's happening easier) and a fresh/clean bucket to do some experimenting. After driving my daughter's JK around while mine is torn apart, I would really love to have heat on the driver's side next winter lol. Her Islander gets so hot that I'm usually turning the temperature dial down quite a bit once everything gets warmed up as it will cook me out!

I was actually really unmotivated to do the heater core once the motor swap was done, so if this can save me that headache, it will be worth far more than the $60 spent! What I think I'm going to do is use it as it comes and do maybe 5-10 gallons of "flush" to see what mechanically can come out (I'll filter it through a coffee filter to weigh and photograph). I may then do a CLR "flush" (i.e. fill up the core with CLR and cap off the hose ends for 30-40 minutes), followed by more mechanical flushing to see what, if anything, comes out further. Obviously, some material will be dissolving and won't be captured in the final "filter", but in my head, it seems that doing a mechanical flush + CLR flush until "clear" of particulates should be a good indicator that nothing else is stuck in there.

Hogges said:

I was about to hack into the dash to install a new heater core, as per the many YouTube videos illustrating how to do it. But I tried a back flush of the heater core first, combined with all new coolant. I used a combination of water from the garden hose and my air compressor, alternating between the two. I flushed in both directions but started from the back side, hoping to clear jammed debris in this way.
It worked! There is still a little bit less heat on the far left vent compared to the others, but a far cry from the ice cold air we had before. I am glad that I tried this less invasive method first.

Click to expand...

Can you see what was jamming up the heater core ?

This is exactly why I’m gonna go full bore with a CLR “pump & flush”…