Refrigerant Oil: Service and Repair
NOTE:- The compressor oil level should be checked:
a. whenever any components (including the compressor) are removed and refitted, or
b. when a pipe or hose has been removed and reconnected or
c. if a refrigerant leak is suspected.
- It is not necessary to check the compressor oil level as part of routine maintenance.
- All compressors are factory charged with 135 ±15 ml (4.6 ±0.5 fl oz) of oil. When the air conditioning equipment is operated, some of the oil circulates throughout the system with the refrigerant the amount varying with engine speed. When the system is switched off, the oil remains in the pipe lines and components, so the level of oil in the compressor is reduced by approximately 30 ml (1 fl oz).
- The compressor oil level must finally be checked after the system has been fully charged with refrigerant and operated to obtain a refrigerated temperature of the car interior. This ensures the correct oil balance throughout the system.
Compressor Oil Dipstick:
The compressor is not fitted with an oil level dipstick, and a suitable dipstick must be made locally from 3 mm (0.125 in) diameter soft wire in accordance with the accompanying illustration. After shaping, mark the end of the dipstick with sixteen graduations 3 mm (0.125 in) apart.
CHECKING OIL LEVEL
1. Open the hood.
2. Fit the charging and testing equipment.
3. Start the engine and turn the temperature control to maximum cooling position, and the air flow control to HIGH speed. Operate the system for ten minutes at engine idle speed.
NOTE: It is important to open the valve slowly during the following item to avoid a sudden pressure reduction in the compressor crankcase that could cause a large amount of oil to leave the compressor.
4. Reduce the engine speed to idling, and SLOWLY open the suction side valve on the test equipment until the compound gauge reads 0 or a little below.
5. Stop the engine at this point and quickly open the suction valve and discharge valve.
Sanden 510:
6. Loosen the oil filler plug and unscrew it slowly by five turns to bleed off crankcase pressure.
Clutch Counterweight Alignment:
7. Remove the oil filler plug. Align the counterweight to the position shown to enable the dipstick to be inserted to its full length.
8. Wipe the dipstick and insert to its stop position, ensuring the angle of the dipstick is flush with the surface of the filler orifice.
9. Withdraw the dipstick and count the number of graduations to determine the depth of oil.
10. Oil level - SD 510: Two to four graduations, add or remove oil as necessary until the mid-range figure is obtained. It is recommended that a syringe is used for adding or removing oil. Use only the correct compressor oil.
11. Lubricate a new O-ring with compressor oil. Fit it over the threads of the level plug without twisting, and install the level plug loosely.
12. Evacuate the air from the compressor using the vacuum pump on the charging and testing equipment, following the equipment manufacturer's instructions. Tighten the filler plug to 8-12 Nm (6-9 ft lbs).
Service Valves:
13. Close fully the suction and discharge valves.
14. Start and run the engine at 1,200 rpm and check for leak at the compressor level plug. Do not overtighten to correct a leak. In the event of a leak, isolate the compressor as previously described in items 4 to 6 and check the O-ring seats for dirt, etc.
15. Stop the engine.
16. Close all valves on the charging and testing equipment.
17. Disconnect the charging lines from the compressor.
18. Be sure service valves are set to the operating position and refit dust caps to valve stems, gauge connections, and to the charging lines.
19. Close the hood.