Subaru Air Conditioning Systems

Fill the compressor with the proper amount of the correct type refrigerant oil.

 

Use of the incorrect type of compressor oil may result in damage to the com-

 

pressor. Refer to Subaru Service Bulletin number 10-37-84, dated 12-12-84, for

 

compressor oil specifications for Matsushita (Panasonic), Hitachi, Lone Star and

 

other compressor types. Always manually rotate the compressor several turns to

 

confirm proper operation after filling with refrigerant oil.

 

Note: The variable displacement Calsonic and DIESEL KIKI compressors

 

may only be filled with special V-5 compressor oil, (D-9OPX). Any

 

contamination with other types of compressor oils will cause

 

compressor damage. Never substitute or cross-contaminate R-12

 

compatible compressor oil with R-134a compatible compressor oil.

Oil Refill

Refer to the Oil Charge Table found in Section 4-7 of the appropriate model

 

year Service Manual. This can be a useful tool to determine the proper procedure

 

to follow and to determine the amount of refrigerant oil to add or replace to the

 

compressor after servicing, repairing, or replacing major system components.

 

Always manually rotate the compressor several turns to confirm proper operation.

Performance Testing

Test Conditions

The vehicle must be indoors or in the shade.

Doors should be closed, all windows open.

Hood open.

Connect the manifold gauge.

Set the mode switch to the A/C MAX position. (On variable displacement compressor system set the A/C controls to high blower and normal A/C.)

Note: When servicing variable displacement compressors refer to Service Bulletin, 10-52-89, dated 07-28-89, for complete compressor diagnostic information.

Set the temperature control to COLD.

Start the engine and idle at 1,500 RPM.

Operate for approximately 10 minutes, then observe the high and the low pressure levels.

An essential step of the performance test is measuring the temperature of the inlet air at the blower and the temperature of the outlet air at the vent grills. The temperature difference should be within specifications for the system. System temperatures will vary with changing conditions, such as high ambient air temperature, humidity, and altitude.

Temperature Measurement

End Wrench

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Subaru R-134A, R-12 manual Performance Testing, Test Conditions

R-12, R-134A specifications

Subaru, a renowned automotive manufacturer, has made significant advancements in its air conditioning refrigerant technologies, particularly in its use of R-12 and R-134A. Understanding these refrigerants is crucial for enthusiasts and technicians alike, as they are integral to Subaru's climate control systems.

R-12, also known as dichlorodifluoromethane, was commonly used in automotive air conditioning systems until the late 20th century. It is a chlorofluorocarbon (CFC) that proved to be highly efficient in cooling systems, offering optimal performance in various conditions. However, environmental concerns over ozone depletion led to a phasedown of its use. Subaru vehicles produced before the early 1990s often utilized R-12, characterized by its stable properties and excellent thermodynamic performance. Despite its effectiveness, the negative environmental impact of R-12 has rendered it obsolete in modern automotive applications.

Adapting to these challenges, Subaru transitioned to R-134A, or tetrafluoroethane, in the 1990s. R-134A is a hydrofluorocarbon (HFC) that does not deplete the ozone layer, making it a more environmentally friendly alternative to R-12. This transition coincided with Subaru's commitment to sustainability and compliance with international regulations. R-134A boasts several advantages, including lower global warming potential and improved efficiency in cooling performance. Its thermodynamic properties provide effective heat absorption, ensuring that Subaru drivers can rely on consistent climate control, regardless of external temperatures.

Subaru has integrated R-134A into its vehicle technology without compromising performance. Newer models utilize advanced HVAC systems that maximize refrigerant efficiency while maintaining comfort. Features such as variable compressor speed control enhance overall system performance, allowing for quicker cooling response and reduced energy consumption. Additionally, Subaru employs meticulous system designs to minimize refrigerant leakage, further supporting environmental initiatives.

The transition from R-12 to R-134A exemplifies Subaru's responsiveness to both performance and environmental concerns. As regulations continue to evolve, it's expected that Subaru will continue to innovate in refrigerant technology, prioritizing sustainability while delivering reliable and efficient climate control for its drivers. As vehicle technology advances, it's clear that Subaru remains committed to adapting its systems for a cleaner, more efficient future.