Whirlpool 8201589 Freezer Fan Motor Assembly OEM Part

16 yr old 42" Kitchenaid Superba KSSP42QKS00 built-in side by side. Freezer not cooling properly (+9 to 18 degrees and refrigerator +32 to +44 degrees). Ran the diag and the evap fan showed code 02 (fan on, but at incorrect speed) all other modules showed code 01 for working properly. So bought the evap fan replacement kit from AppliancePro who as usual had the best price and support. Swapping out the fan was easy: take all the freezer shelves out, take two of the drawer guides out, two of the shelf posts out and then a bunch of metal screws to get the thin aluminum shield out. Even tho the kit came with wire harnesses for diff models and what looks like a thermostat to clip onto the cooling line (for the defrost function perhaps?), I swapped out just the fan. Its held in by plastic U arm and requires no tools to remove after prying off the fan blade. The fan wire pig tail fits into the existing harness and just reverse the steps to put everything back. The diag now shows fan as code 01 and working at right speed! But sad to say, the freezer still was not cooling. Brought in a tech and he said low freon in system so now looking at an expensive leak detection and coil swap out. Debating whether worth it on a 16 yr old appliance (manufactured 04/2002) or should I spend the $7K and get a replacement GE or LG that will fit in this built-in space. Models under consideration are: LG Studio LSSB2692ST and GE Cafe Series CSB42WSKSS. Regular counter depth refrigerators while having larger capacity and cheaper are not an option as its a bullt-in space of 26" depth x 42" width and 84" height in a upscale kitchen. Thoughts?

Replaced fan motor, fan, and wiring harness.