Whirlpool refrigerator (top mount freezer) model...

Question

My refrigerator and freezer temp dropped overnight. The fan is running. It is auto-defrost. I cleaned the coils which are located on the bottom--they were very dirty. I let it sit for 2 days and turned it back on--it started to cool at first, but then the air that the fan was blowing turned warm within a few minutes and I am hearing a repeated clicking noise. The frig is approx 6 yrs old, so I am wondering whether or not to just replace it or try to correct the problem--any suggestions? Thanks!