For this job, I was performing routine maintenance on an AC. Upon checking the system. I came across high static pressure. called the supervisor to come diagnosis issue further. However, soon after checking the outdoor unit, I could see that the refrigerant levels were way too low. The system is operating as if it was 100° day. After checking inside it was clear that the TXV was not functional and the coil itself has a leak in the lower right part of the A-frame. Because of this replacement of the AC coil is necessary. I think full system replacement would be a better option, because system is 12 years old and both the furnace and AC are showing other signs of failure in regards to the motor and the heat exchanger. Before AC replacement is recommended. Full system replacement would be even better.