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Wednesday, 4 July 2012

Is Universal Compressor Oil Really Universal?

Universal compressor oil may not be that universal!

If you’ve got an automotive aircon repair shop, the cost of carrying all the specialised grades of compressor oils is probably killing you? I’m sure you’ve thought about using a universal compressor oil; but could you use this in all applications?

With mineral oil, ester oil, and three common viscosities of PAG synthetic air compressor oils in use, one type of oil that will work in everything definitely seems like a logical approach.

However, is there really
a “universal” oil that can be used for all applications? It almost sounds like something that is too good to be true.

Can a universal compressor oil be used in all applications.

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. But even worse; under the “right” conditions, it could create a severe shock hazard to the technician, and OEMs have issued stern warnings about it.

So for this, we’d definitely not be able to use a universal compressor oil.

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.

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 compressor oil be used in them?


 There are companies that sell oils (both ester and PAG) that are advertised as being universal compressor oil, that can supposedly be used in anything (except the hybrids referenced above) and with both R-12 and R-134a. But using these “universal” oils 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 compressor oil you can end up with one that is too viscous for some applications while being too light for others. While that may not make a big difference in some air 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 be doing if you add a universal compressor oil to an R-12 system that contained mineral compressor oil.

Using universal compressor oil can void your warranty.

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 compressor manufacturers.

Large sums of money are spent doing research into determining the proper viscosity and blend of 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, and that means staying away from universal compressor oil. 

Before you lay out money for a universal compressor oil that may just be snake oil, first consult the professionals at Habot Synthetic Lubricants.