Just like our rear brake calipers we are having original Cores rebuilt by a top-quality company. We did offer these on an exchange basis, but our rebuilder is retiring so we will be unfortunately discontinuing this service. We are expecting two more back before he officially retires and will add them to inventory when they arrive. We are now selling these outright with no core charge and once our inventory is completely gone, we will remove this from our site. It is STRONGLY recommended that you replace your receiver dryer, liquid line and condenser when servicing your system...Follow the R134 conversion procedure with proper O-rings and compressor oil when you install. If your old compressor suffered a failure that sent metal through your system then you will have another failure with the replacement compressor.