I recently inherited a 2008 Grand Cherokee from my son-in-law. The A/C had stopped working and he took it to Mr Tire and they installed a new compressor. He didn't have enough money to get the full job done, so he only had the Compressor installed. He did not have the Evac & Recharge. Wanting to keep the Compressor Warranty intact, against my better judgement, I took the car to my local Mr Tire to have the Evac & Recharge done. Within 50 miles of use, the A/C stopped putting out cold air. I checked under the hood and I saw bubbles coming out of the low pressure valve. I check the valve and it was tight, so I pressed it in a few times and the bubbles stopped. I assumed I had a low charge due to the gas leaking out of the valve. I took it back to Mr. Tire and they said they would Evac & Recharge again. They then called me and said after Recharging, the A/C was still not putting out cold air and they felt my Expansion Valve was bad. I approved another $138 for the new valve and they agreed to do the Evac and Recharge for free, They then called and said they found desiccant ***** in the old Expansion Valve and I needed a new Filter Dryer. They said when the compressor went bad, it probably destroyed the Filter Dryer and crap went into my system, they also said they couldn't guarantee the rest of the system did have crap in it. I'm a fairly good mechanic, and I'm not afraid of tearing things apart and learning new things. I also have access to a vacuum pump and gauges. I really don't want to keep throwing money to Mr. Tire. What should I do? Based on the history provided, should I tear the system down and install a new Filter Dryer? Can I flush the Condensing Coil and or Evaporator Coil. Any help and/or direction would be greatly appreciated.