However, here's a general outline of the process involved – again, this is NOT a DIY guide, consult a professional:
1. System Evacuation and Inspection:
* The system must be completely evacuated of all remaining R-12 refrigerant. This requires specialized equipment to pull a near-perfect vacuum. Any remaining R-12 needs to be recovered properly, as it's a regulated substance.
* A thorough inspection is crucial to check for leaks, worn seals, and other issues. R-12 systems are often older and may have components that are worn or damaged. These need to be repaired or replaced *before* converting to R-134a.
2. Component Changes/Modifications:
* O-rings and Seals: R-134a requires different O-rings and seals that are compatible with the new refrigerant. These are often made of a material that is resistant to the properties of R-134a. All O-rings should be replaced.
* Expansion Valve/Orifice Tube: The expansion valve or orifice tube may need to be replaced or adjusted, as the different properties of R-134a require different metering devices to ensure proper refrigerant flow.
* Compressor Oil: The compressor oil used with R-12 is not compatible with R-134a. The system needs to be flushed and the compressor oil replaced with an oil compatible with R-134a.
* Accumulator/Drier: This component filters contaminants and absorbs moisture from the refrigerant. It's highly recommended to replace this during the conversion process.
3. Refrigerant Charging:
* Once all modifications and repairs are complete, the system is charged with the appropriate amount of R-134a refrigerant and PAG oil (polyalkylene glycol). The amount will vary depending on your system's specifications, typically found on a sticker in the engine bay or in your owner's manual (if you have it). Incorrect charging can severely damage the compressor.
4. System Leak Check and Vacuum Test:
* After charging, a leak check is performed to ensure the system is airtight. Another vacuum test confirms the system is leak-free before operating the A/C.
Important Considerations:
* Legal Restrictions: R-12 is a controlled substance. You cannot simply let it out into the atmosphere. Proper recovery and recycling are mandated.
* Complexity: This process involves specialized tools, knowledge of automotive A/C systems, and experience working with refrigerants.
* Cost: The cost of conversion can be significant, often exceeding the value of the vehicle, especially considering labor costs.
In summary, converting your van's AC system is a complex task best left to experienced professionals with the proper equipment and licenses to handle refrigerants. Attempting this DIY could result in costly repairs, environmental damage, and potentially harmful exposure to refrigerants.
