A/C On Hybrid Vehicles - What You Need To Know

Besides the fact that R-1234yf and R-134a are out there, and we need to be aware of those differences, the A/C system on some hybrid vehicles remains an area of concern.

We've been getting an increasing number of questions regarding the procedures, OEM requirements, and general cautions related to the evacuating, recycling, and charging procedures required for servicing the air conditioning (A/C) systems on hybrid vehicles using R-134a (aka HFC134a). These are the systems that have high-voltage (HV) electric compressors rather than the conventional belt-driven types that we have been working on. Although there are many issues related to HV electric compressor systems that need to be understood, here are some high-level, need-to-know facts.

  1. DO NOT attempt to service these systems without getting the proper training first!
  2. R-134a HV compressor systems use the same size service ports as the conventional R-134a systems.
  3. HV compressors require special Polyol Ester (POE) A/C refrigerant oil that is non-conductive. The specific type of oil is identified by the vehicle maker. All non-condutive POE oils are not the same!
  4. A/C equipment that has been used for conventional A/C systems can contaminate the HV powered system.
  5. As little as 1% standard PAG oil can reduce the dielectric properties of the approved POE oils and damage the system.
  6. Per the vehicle maker, many of the A/C system parts will require replacement if the system is contaminated.
  7. SAE J2788 compliant machines do not have oil injection to avoid cross-contamination of oils.
  8. A straight-forward approach to avoid cross-contamination is to use dedicated hoses and injectors for each type of refrigerant oil.

In summary, it is very important to recognize the differences between conventional and HV electric compressor A/C systems and obtain the proper training, the required equipment, and use the specified refrigerant oils to ensure the complete, safe, and quality repairs to these A/C systems.

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