Automotive AC Repairing and Replacing – Replacing the AC Compressor

1. After recovering the AC system or verifying the system is empty,the compressor removal process can begin.
2. Remove the fasteners for the suction/discharge line.


After recovering the refrigerant from the system with an approved machine, the AC lines at the compressor can be removed. This suction/discharge line is held in place with a bolt.

3. Remove the drive belt.


A belt removal kit is often needed when removing and installing serpentine drive belts. These kits are specially made to make it easier to gain access as well as have the required leverage to make belt service much


After choosing the correct parts of the belt service kit, the tool is installed on the belt tensioner to release pressure on the belt and allow it to be removed from the belt train. Close attention should be paid to identify the correct routing of the belt. There will nearly always be a belt diagram on a decal under the hood to assist in the belt

4. Remove the electrical connections of the compressor.
5. Remove the compressor mounting fasteners.


The compressor coil and the pressure switches must be carefully disconnected by releasing the locking tabs and pulling the connector apart. It is easy to break these plastic connectors, so caution should be used to prevent

6. Inspect the old compressor next to the new compressor. It is important to make sure that the correct unit is used. The shape of the body, the diameter and number of belt grooves, the electrical connector, and the location of the suction/discharge port should be closely checked.


The new compressor should be closely inspected to make sure it will fit properly. The recommended way to ensure that the new compressor is correct is to lay it next to the old compressor and closely look at all parts of the items to make sure that the new unit will fit properly. Key parts of the units to check closely include the location of the holes for the mounting bolts, the diameter and number of grooves on the pulley, the location for mounting the suction/discharge line, and the connectors for the compressor clutch

7. Follow the directions for the compressor manufacturer concerning the refrigerant oil in the new compressor.


Most new compressors will have a tag or a sticker on the compressor body that give instructions on what to do concerning refrigerant oil. These instructions should be followed to ensure that the oil level and type will be used for the system. If there is not an oil tag with the new compressor, then the old compressor should be drained into a measuring container. The amount that was drained from the old compressor should be added to the new compressor. If the amount was less than 2 ounces, then 2 ounces of new oil should be added to the new

8. Reinstall the compressor using the correct mounting fasteners. Get all of the fasteners started by hand before torquing any of the fasteners to specifications. It is very important to closely follow the exact torquing procedures to prevent putting the body of the compressor in a bind and causing early failure of the unit.
9. Reinstall the electrical connections to the compressor. Make sure that each connection is securely installed and locked into place.
10. Install the compressor belt and adjust it to specifications if it is adjustable. Check the belt for proper routing and alignment into the correct grooves.


The belt tool is used during the belt installation. This tool aids in releasing the spring-loaded belt tensioner by giving strong leverage to the user. The belt should be closely inspected following installation to make sure that it is routed correctly and that all of the grooves are aligned on the pulleys and

11. Install the suction discharge line, being sure to use new gaskets and seals. Torque the fasteners to the correct level.
12. Install the rest of the parts from the compressor kit using the correct techniques as listed in this chapter. The AC system can be evacuated and recharged before being returned to service.
13. The AC system can be evacuated and recharged before being returned to service.

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