Chosen Solution

A leak in the refrigeration system on an LG model number LFX 28978ST.

If you really have a refrigerant leak, you will most likely not be able to repair it yourself. I had that problem in my SubZero. The tech came out and put a new evaporator unit in the refrigerator part, then evacuated and recharged the system. All that required some specialized tools and knowledge. So, what, exactly, are your symptoms?