Converting Cars from R12 to R134A Freon
Discover some of the most important steps when converting cars from the old style R12 Freon to the more environmentally friendly 134A refrigerant. Review symptoms and problems created from improperly converted systems. Learn about common short cuts that can cause premature failure of expensive components a year down the road.
Do You Have to Convert
If you have an automobile from the mid-90s or older you most likely own an air-conditioning system with R12 Freon installed. I provide additional information and some AC service tips for old cars on a previous article that can help you decide how to proceed with needed repairs. The short answer to the question, do you have to convert an R-12 system, is no you don’t. If the air-conditioning is functioning properly, and no service is required then no action is necessary.
On the other hand, if the system is low, or service is required than the answer is you probably should convert the system. If you plan on keeping this automobile, or handing it down through the family then you have a vested interest in making sure the procedure is done correctly. This next section will provide some basic knowledge of what should be done so you can follow up with your mechanic to assure longevity and proper operation are the end results.
Freon Replacement Procedures and Guidelines
There are two major obstacles to overcome when converting from R12 to 134A Freon. The first is these air-conditioning systems use different lubrication oil and are not cross compatible. The second problem is they operate at slightly different optimal pressures. Here we’ll talk about overcoming these two hurdles.After the R12 is removed and stored in a dedicated recycling machine the next step is to remove as much of the old oil as possible. There are a few places where this will collect. The largest source will be the compressor, but some will also wind up in the AC accumulator. Drain and measure the oil from the compressor and accumulator.
On reassembly the Technician will add the specialized polyalkylene glycol PAG oil to the compressor and the replacement accumulator.After the work is completed conversion fittings will be installed over the high and low side service ports, so specialized R134A tools and equipment can be used from this point forward. Before the system is refilled with Freon it must be vacuumed for thirty minutes to remove any moisture. It’s important that only 80 percent of the original charge be installed when refilling, because these refrigerants provide optimal operation at different pressures. Finally conversion labels are installed over the vehicle’s original labeling indicating completed conversion.
Common Conversion Short Cuts
When a Technician takes shortcuts he jeopardizes the longevity of the air-conditioning system. Unfortunately, mechanics are usually paid on a flat rate basis where time equals money. Even the best people can be put into a situation where they find it necessary to rush a repair. Converting from R12 to 134 is an operation requiring patience. Draining the oil out of the compressor and accumulator takes time. If this is rushed, incomplete removal is the result. Oil left behind can thicken over time causing improper lubrication of internal components. The severity of this and the damage it causes is directly related to how much remains. Another common conversion shortcut is the third largest collection point for old lubricant, not mentioned above.
The AC condenser can also hold a decent amount of oil. The amount depends on the design and the number of coils in the condenser. Thoughtful mechanics will take the time to flush out any lubricant from this component with a specialized flushing agent.Another common mistake is to ignore the accumulator. Although it’s tempting to reuse this item there is a bag of desiccant at the bottom that protects the system from moisture. This desiccant reaches its maximum absorption quickly. In some cases the material is wrapped in a cloth bag that can hold some of the old lubricant. No one likes to spend money on a part that’s not broken, but replacing this component is critical to a long lasting conversion.
Symptoms of Improper Conversion
The most common complaint after a system is converted from R12 to 134A is the output temperature at the vents feels warmer than it did with the old Freon. This is to some degree a normal condition as the new Freon doesn’t really work as well as the old stuff. The total difference should only be a few degrees. If the interior cabin doesn’t cool on a hot summer day when the air-conditioning is set to the recirculation mode on high blower within ten or fifteen minutes further AC diagnosis should be performed.