Professional Tips on Oils

Modern compressors need to have the correct type and viscosity of oil in them.

An incorrect oil will have a detrimental effect on the operation and performance of the compressor.

Even more so with the new breed of hybrid vehicles. They have an electric driven compressor that needs a non-electrically conducting oil. The wrong oil will burn the compressor out!


Compressor Oils explained

PAG (polyalkylene glycol)

These are the most commonly used compressor oils in automotive applications. They’re used in both R134a and R1234yf systems.

The makeup and design of the oil may differ between the refrigerant types. Not all PAG oils are the same and there is a number of viscosity bands too.


PAO (Polyalphaolefin)

PAO is a fully synthetic non-hygroscopic oil. They don’t readily absorb moisture and are recommended for R134a systems only.



POE is a synthetic oil. They have high thermal stability and are mainly used in refrigerated systems and large coach applications.


The Problem of moisture in PAG oils

PAG oils readily absorb moisture or water. This can lead to the formation of acids within an air conditioning circuit. This can cause corrosion and allow the refrigerant to escape through a failed part. R134a systems are in the main fairly robust, but moisture ingress has lead to a lot of condenser and evaporator failures.


The problem is even more profound with R1234yf systems. 

It’s essential the oil being injected is moisture free, otherwise failures will happen.


WAECO moisture free PROFI oil system

All current WAECO air conditioning service machines are designed to accept the patented oil and dye canisters. The contents are sealed in a moisture free bag. This means the oil will have a long shelf life and no moisture is being introduced into the A/C circuit inadvertently. There’s no messing about tipping oil into bottles. It’s a clean and neat solution to what can be rather messy.


Standard 250ml Oil Cans 

Waeco oils available in 250ml metal cans. Resealable lid stops the ingress of moisture meaning the oil has a long shelf life. Compatible with all makes of air con machines that have separate oil containers.


UV Leak detection

UV dye is an excellent way of finding refrigerant leaks. However poor quality products can cause compressor wear and o-ring seals to leak. We supply high quality WAECO TRACER UV additives that have been tested and approved to be used in all automotive air conditioning systems.