Courtesy of MACS Member 1-800-Radiator & A/C’s Training and Tech Support
This article originated as an answer to a question asked by a warehouse operator seeking information for a customer. To provide an accurate reply, the Training &Tech Support department checked with a combination of compressor suppliers, lubricant providers and others.
It’s not unusual for a customer to call and say “I want some of that oil I can use in everything.” Or when engaging a technician in a conversation about A/C, for them to say “I use universal oil, because I can only put one type in my A/C machine, and just to keep it simple, I use it in everything.”
With mineral oil, ester oil, and three common viscosities of PAG oil in use, one type of oil that will work in everything sure seems like an easier approach. However, is there really a “universal” oil that can be used in everything? It almost sounds like something that is too good to be true.
Well that is the case, so let’s examine it. First of all, hybrid vehicles that use compressors which have an internal electric motor require specially formulated ester oil. Use of anything other than this type of lubricant with these units can cause severe compressor damage, and will void compressor manufacturers’ warranties. Even worse, under the “right” conditions, it could lead to the possibility of a severe shock hazard to the technician, and OEMs have issued stern warnings about it.
Going a step further, equipment such as manifold gauge sets and recovery/ recycling/ recharge machines that are used on non-hybrid systems cannot be used on these hybrids, because of the possibility of contaminating the system with traces of lubricant other than the specially formulated ester oil. Note: Many hybrids utilize belt-driven compressors which require conventional PAG oil. So what about non-hybrid vehicles, and hybrids that have conventional compressors which use PAG oil? Can universal oil be used in them?
No!—at least not without encountering increased risk as opposed to using the specified oil.
There are companies that sell oils (both ester and PAG) that are advertised as being “universal” that can supposedly be used in anything (except the hybrids referenced above) and with both R-12 and R-134a. But their use is a recipe for potential problems. There is a difference in the viscosity (thickness) of PAG 46, PAG 100 and PAG 150. You can actually see the difference by observing each being poured from their respective containers.
With that being the case, when utilizing a universal oil you can end up with one that is too thick for some applications and too thin for others. While that may not make a big difference with some compressors and the oil may work, there are others where the correct viscosity is critical, and the use of anything other than what is recommended can cause excessive noise or premature compressor failure. Also, if you just need to add some oil to a system, it isn’t a good idea to mix different types of oils, as you would do if you add universal to an R-12 system that contained mineral oil.
With all the lubrication problems that can be encountered with R-134a systems, a “one size fits all” approach isn’t a good one. Plus, using anything other than the specified viscosity of PAG oil in systems that require it voids the warranty from many of those compressor manufacturers.
The manufacturers spend large sums of money doing research to determine the proper viscosity oils to use with their compressors. To avoid the possibility of voiding warranties and reduce the likelihood of premature failures, it’s necessary to stick with their recommendations.
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When having your mobile A/C system professionally serviced, insist on proper repair procedures and quality replacement parts. Insist on recovery and recycling so that refrigerant can be reused and not released into the atmosphere.
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The 33rd annual Mobile Air Conditioning Society (MACS) Worldwide Training Conference and Trade Show, Be the Best of the Best will take place February 7-9, 2013 at the Caribe Royale, Orlando, FL.