Stains, they removed the engine in my 2010 wrangler, removed all 8 freeze plugs and heads to flush the engine of casting sand which they claim is what clogged the heater core. Before that, they had tried flushing the core which was a band aid approach because the problem of not enough heat returned in a short time. All told in three weeks they replaced the radiator water pump and the heater core. I also contacted jeep customer service and had a case number assigned. There are others who have the same problem. Much more detail in the wranagler forum http://www.*************.com/f33/201...ue-130335.html

 

Update: got the car (2010 wrangler 18k) back and the duct work that I found under the seat (which they forgot to reinstall during heater core repair) was indeed the cause of lack of heat directed on the driver floor area. Everything working fine now and they also checked the in line filter which was free of sand. So, after more than 3 weeks (off and on) in the shop: engine removed and dissassembled including heads to facilitate flushing "casting sand" from the block, new heater core, new radiator, new water pump. When the engine block was broken down they used a power washer to get the sand out of the nooks and crannys. The head mechanic I have been speaking to all along maintains it is casting sand and that it has a pinkish color. That may have something to do with the orange colored coolant. Having Chrysler customer service involved in detroit with a case number helped. They have to authorise the rental.

 

well as of this morning all my vents are now blowing cold air, here's my thread
https://www.jk-forum.com/forums/show...ver-side-vents

 

 

Here's a video I did this weekend to help flush the casting sand, and installed a filter screen.

 

This video is excellent. I used it this weekend with a slight modification.

I found that when I was emptying my drain bucket, the hoses would empty and when I started spraying again I would get a larger amount of trash. I pulled my air hose out and started alternating between air blasts and water blasts and the volume of trash increased significantly. Ended up with excellent heat today.
Thank you for your video!