General Information For Replacing Components
- Any refrigerant circuit components submitted for quality observation must be sealed (use the original caps from the replacement part).
- Replace damaged or leaking refrigerant circuit components. Refer to COMPONENTS, REPLACING .
- To date, the replacement parts A/C compressor, receiver/dryer, evaporator and condenser have been filled with nitrogen gas. This charging stops gradually or the charging pressure is so low that gas does not escape noticeably when opening.
- On vehicles installed with a compressor with no A/C clutch, the engine is only to be started following complete assembly of the refrigerant circuit (A/C compressor always in operation as well).
- When the refrigerant circuit is empty, the A/C compressor with A/C Compressor Regulator Valve -N280- (without A/C Clutch -N25-)is switched to internal lubrication with the result that only a minimal amount of oil is pumped from the compressor into the circuit.
The following replacement part (A/C compressor, reservoir, evaporator and condenser) can be filled with nitrogen gas, this filling is not always present. Therefore little or no pressure equalization is noticeable when unscrewing plugs from replacement parts.
Depending on the storage location and storage time, components which were filled with nitrogen gas from the manufacturer little or no pressure equalization is noticeable when unscrewing plugs the first time, so it is not possible to make a prediction about the presents of leaks in the components. So for example the nitrogen gas which was filled via the shaft seal from a replacement part A/C compressor can flow out over time via the shaft seal although the A/C compressor does not have any leaks.
As parts are sometimes stored for lengthy periods and at different locations within the spare parts organization, it is entirely possible that gas will escape from some parts and not from others on initial opening (even in the case of identical spare part numbers). Sealing caps at replacement part connections are therefore to be removed carefully and the nitrogen gas allowed to escape slowly.
There are one or two expansion valves and a receiver/dryer or dryer reservoir installed in the refrigerant system. Refer to Refrigerant Circuit (vehicle-specific service information).
Replace the dryer cartridge or components with desiccant bag (receiver/dryer) after cleaning (flushing with refrigerant R1234yf refer to REFRIGERANT CIRCUIT, CLEANING ) the refrigerant circuit at the same time hold sealed as long as possible so that the absorption of moisture is as little as possible.
Replace the dryer cartridge or the components with a desiccant bag (receiver/dryer) if it is required for certain repair procedures or if the refrigerant circuit has been open for a longer period of time and moisture has gotten in (after an accident, for example). Refer to LEAKING OR DAMAGED COMPONENTS, REPLACING, EMPTY REFRIGERANT CIRCUIT EXCEPT A/C COMPRESSOR AND RECEIVER/DRYER .
The period of time which a refrigerant circuit may be left open without having to replace a component with the desiccant bag (receiver/dryer) depends on ambient influences to a large extent. Given a high ambient temperature and a high humidity level or if the vehicle, for example, has been standing in the open or driven (in wet, foggy weather conditions), the period will be considerably shorter than for a vehicle which has been standing in a heated dry area. The size of the opening through which moisture may ingress into the circuit also influences the period for which a refrigerant circuit can be left open without having to replace the component with the desiccant bag. Refer to LEAKING OR DAMAGED COMPONENTS, REPLACING, EMPTY REFRIGERANT CIRCUIT EXCEPT A/C COMPRESSOR AND RECEIVER/DRYER .
Seal open connections and pipes (to prevent absorption of moisture).
Dispose of dirty or used oils of unknown origin paying attention to local regulations.