Just wanted to get some opinions on diagnosing an old R-12 Walk-in cooler running 416a. Not pulling down the temp to an acceptable level.

Here are the operating parameters available to work with.
- System is air defrost only, TXV metering.
- Condenser (steel fins) and Evap are unobstructed, air flow looks good.
- Liq pressure 175lb, Saturation temp 130 degrees, Liq line temp 148 degrees. (Yikes Hot! -18 sub-cooling???)
- Suct line Pressure 20, Saturation temp 30 degrees, Suct line temp 59 degrees
- Condenser Ambient 90 degrees, outlet temp 110 degrees, = 20 degrees heat rise

What's your guess as to what is ailing this system? ( besides being obsolete )
How would you proceed?

Would love to hear the suggestions/ideas/opinions from the community.
Thanks