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Can You Mix Pag and Poe Oil | Things You Should Know

PAG and POE both are synthetic oil, but they have some distinctions. The Poe oil is used in the refrigeration system of your vehicle. You can also use this oil in any automotive AC system. Notably, the Poe oil is mainly made for the r-134a motor engine.On the other hand, the Pag oil is mainly a lubricant for the compressor. You cannot use it for other engine oil.

Since these two oils are different, you may ask, “Can you mix Pag and Poe oil?”. You will get the answer to your query from this write-up on Poe Oil vs. Pag oil.

Can You Mix Pag and Poe Oil

Can you Mix Pag & Poe Oil?

No, you cannot mix PAG & POE oil. As both of these oil are developed for different purposes and have different properties. Mixting PAG and POE oil together will alter their properties and can seriously compromise their working.

Polyester, also known as POE, is the synthetic oil most commonly used in refrigeration systems that use HFC refrigerants. It is also appropriate for refrigeration systems that use CFC and HCFC refrigerants, and it is currently being tested for use in CO2 refrigeration systems.

Polyalkylene Glycol, also known as PAG, is a type of synthetic oil utilized most frequently in R-134a-based automotive air conditioning systems. Even though it is more hygroscopic than POE oil, it does not hydrolyze when exposed to water.

Because the two oils do not combine entirely and cannot produce a stable homogeneous mixture over time, the mechanical parts of the compressor cannot receive the adequate lubrication they require. At first glance, oils that have been mixed will appear to be thoroughly combined.

However, after a brief period in which the compressor is turned off, the two oils will begin to separate back into their original states. When the compressor is started from a cold state, separated oil with a higher density and viscosity will lead to restricted lubrication of precisely fixed moving elements within the AC compressor.

Why can you not mix Pag & Poe Oil?

PAG and POE both are synthetic oil and have more or less the same application is automotive AC system. So why you cannot mix PAG and POE oil. Well its because of their different chemical composition, viscosity, and additives. Both are developed to serve one specific function and mixing both will compromise their ability to work.

It is never recommended to mix PAG and POE oil based on the below mentioned factors

  • Compatibility
  • Viscosity
  • Hygroscopicity
  • System Clogging


Both POE and PAG oil are engineered to work best in certain conditions, certain refrigerants, and a certain output is being accepted from them. Mixing both oil will not develop a solution that work better or give same result as any of these deliver separately.

POE oil work as lubricant when used with HFC-134a and it is used as a replacement of CFC-12. PAG on the other hand is used in refrigeration system of car that use R-134a and R-1234yf refrigerants. So POE and PAG are incompatible with one another. You are only allowed to use a single kind of oil in the system, and that oil must be either all PAG or all POE.

Hygroscopicity & Viscosity

Another reason you cannot mix PAG 46 oil & POE Oil is that they are hygroscopic by nature, which means they can take in moisture from their surrounding environment. The ability of an oil to absorb moisture and turn into a saturated state is referred to as hygroscopicity and both oil have different level of hygroscopicity. Typically, PAG oil has a higher amount of hygroscopicity than POE oil. As a result, mixing these two oils becomes a real tough job.

System Clog

As both oils have different viscosity grades, different chemical composition, difference in ability to absorb moisture, and use different additives. So mixing them can creat an oil that can lubricate system properly and may decompose or deteriorate into a mixture that clog the entire AC system.

pag oil 46


Is it safe to mix Pag & Poe Oil?

It is not safe to mix Pag & Poe oil. These two are different types of oil. Mixing these two will creat a mixture whose properties and working cannot be determined. So you should not mix PAG and POE oil.

What can I use instead of PAG oil

PAO oil (Polyalphaolefin) is a multigrade synthetic oil and is good alternative of PAG oil. It is compatible with wide varity of refrigerant and AC systems.

Can you replace POE with PAG

No, you cannot replace POE with PAG until the AC system manufacturer recommends or allow to do this. Both the different composition and work differently with different refrigerants.

Closing Words

Can you mix Pag and Poe oil? The direct answer is no; you cannot mix these two different oils. They are not compatible with each other. It’s better to avoid mixing them to get a safe automotive engine.

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