AC Lubricants – it’s not that simple

Airstal Technical Service Bulletin ATSB 83 / 05-2017

The lubricant is a very critical component of the automotive AC system. Besides lubricating all the moving parts in the AC compressor it also has to mix

very good with the refrigerant in order to circulate through the system and back to the compressor again.

In a proper working AC system there will always be approx 40% lubricant inside the compressor while the remaining 60% is on its way around in the

system. This balance is very important for the system. Therefore it’s also very critical that there is enough oil inside the system in order to secure a stabile

lubrication flow at all time.

Until 1987 all AC systems were charged with Freon (R12). The best lubricant for R12 was mineral oil; it was simple and cheap and mixed very well with the

refrigerant.

After 1987 R12 was banned (due to its negative effect on the Ozone layer) and the automotive industry had to implement R134a instead. The properties of

R134a are quite different than the ones in R12 so a new lubricant had to be developed and the choice fell on a substance called Poly Alkylene Glycol (also

called PAG)

There are generally 3 lubricant “scenarios” - or we can also call it stress - that takes place inside a compressor:

Hydro dynamic stress

Elastohydrodynamic (EHL) stress

Boundary / Extreme pressure (EP)

AC compressors are designed to work in conditions where the moving metal surfaces are always separated from each other by a lubricant film. But in the

real working conditions on the vehicle metal to metal contact DOES occur from time to time – for instance during:

The ON-OFF cycle

AC Lubricants – it’s not that simple OR under excessive load.

Or partly contamination of the AC system (resulting in too bad oil circulation)

Lubricant starvation due to restrictions inside the AC system.

In such conditions we talk about the need for Boundary lubrication, which can be achieved by mixing additives into the lubricant – it’s of course very

important that all these additives are 100% compatible with all the system components too.

Please refer to the ATSB 84 where you will find the more detailed PDF version of the development of lubricants for Automotive A/C systems (Author W.L

Brown Union Carbide Corporation)

Nowadays there are several categories of lubricants such as:

Mineral oil – is mostly used in systems that is charged with CFC or HCFC or Ammonia.(Older systems)

Alkyl Benzene oil – mostly used in R22 systems

PAO oil – this oil is best described as “mineral synthetic” because its chemical structure is similar to mineral oil but formulated by so called

monomers. Works good with R22 and Ammonia

PAG oil was the first oil that was developed for use in HFC refrigerants and it mix very well with these refrigerants. The main concern with PAG oil is

that they are very hygroscopic. PAG oil is also incompatible with copper and precautions have to be taken not to use it in systems containing much

copper components. PAG oil also mixes very well with Ammonia.

POE oil is the second generation of lubricants for HFC refrigerants. POEs are very good lubricants and less hygroscopic and more chemically stabile

than PAG when presence of water. POEs can be used in all refrigeration and AC systems. POE oil is 4-5 times more expensive than Mineral oil and

Alkyl Benzene Oil and that is also a reason why it has not become the first choice for the Car Industry.

AC Lubricants – it’s not that simple As per 2017 it’s no longer allowed to use refrigerant R134a in any new vehicle sold in EU so therefore another refrigerant called R1234yf has been

introduced.

R1234yf has a GWP (Global Warming Potential) on 4 (against 1430 for R134a) and it’s now the preferred refrigerant for all new cars sold in Europe.

R1234yf is very similar to R134a but it shows less solubility with “normal” PAG oil and several tests have shown that it’s more unstable and it’s even able to

“split” into two liquid phases reducing the oil circulation

So the final technical conclusion of the car producers and AC system producers is that it’s not acceptable to use an-of-the-shelf POE or PAG in an R1234yf

system.

Therefore new improved PAG oil has been developed. It contains additives that improve:

Anti-corrosion

Anti-oxidation (Moisture in a R1234yf system is more critical than in a R134a system)

So the lubricant manufacturers have made improvements both of the molecule structure of the base components of the oil blend and on the lubricant

additives (anti-corrosion, anti-oxidation, anti-wear, anti-seize, with particular care to the anti-oxidation) and finally they ended up with a new PAG that is

compatible with both R134a and R1234yf.

Now there are already several OEM PAGs for R1234yf available on the market – and also we see a few aftermarket versions too. Below you will find some

examples from the OEM world:

Sanden has made a version that they call SP-A2 and they use it in both their mechanical and electrical compressors – that very interesting indeed due to

the fact that most of the other OEM producers use POE oil with a very high di-electrical strength in order to avoid any possible conflicts between the motor

windings and the lubricant. It might be that Sanden have added some features that improves the di-electrical strength so it reaches the same level as the

POE has...it will require a separate analysis and test to find out the di-electricak strength of the SP-A2.

AC Lubricants – it’s not that simple Denso use a version they call ND-12 and it’s a so-called double end capped version (DEC). Basically DEC means that the oil is less sensitive to moisture and

that’s a very positive feature. Generally ALL Denso AC lubricants are DECs – Airstal recommend that all workshops should use double end capped oils – that

would be the best solution for the whole Automotive Industry.

Doowon / Hanon use a version they call FD46XG – Not much information is available on this product at the time of writing this bulletin.

Delphi / Mahle use the same type as Sanden - We assume that they simply developed this lubricant in cooperation with Sanden.

Valeo use a version they call VCxxxYF - Not much information is available on this product at the time of writing this bulletin.

By the way! There is one more lubricant that we also need to know about:

Mercedes and other luxury brands have already developed AC systems charged with CO2 and these systems we will soon also see the workshops for service.

CO2 is the ideal refrigerant seen from the environmental point of view due to the fact that its a natural ingredient of our planet.

However the function and lubrication of a CO2 AC system is more complex compared with the R1234yf system and tests have shown that CO2 is actually

able to neutralize some of the lubricant properties. Below a short list of lubricants that can be used in CO2 systems:

PAO (Poly Alpha Olefin)

AN (Alkyl Naphthalene)

POE (Poly Old Ester)

PAG (Polymers of Alkylene Glycols)

AC Lubricants – it’s not that simple AN / PAG

It’s very possible that each OEM producer will make their own variant of the lubricant that they consider as the best one for CO2 systems, but there is a very

high chance that it will contain some of the above mentioned ingredients.

Below you will find our most up-to-date AC lubricant oil chart and our equivalent part number and notes

OEM Producer OEM AC

Lubricant ref. Equivalent

Compattible with

Refrigerant Airstal

catalogue ref. Note 1 Note 2

AC Delco PAG 56 / S10X PAG 46 HFC134A 113-9104M

AC Delco PAG-PSD1 PAG 46YF HFC134A 113-9108

AC Delco PAG-PSD1 PAG 46YF HFO1234YF 113-9108

Bosch D-90PX PAG 100 HFC134A 113-9105M

The D-90PX was used in R12 systems - Must be retrofitted into R134a R12 is illigal

Calsonic Kansei DH-PS PAG 46 HFC134A 113-9104M

Calsonic Kansei DH-PR PAG 100 HFC134A 113-9105M

DAC FD46XG PAG 46YF HFO1234YF 113-9108

DAC FD46XG PAG 46YF HFC134A 113-9108

Delphi PAG OIL RL-897 PAG 46 HFC134A 113-9104M

Delphi PAG OIL 9986181 PAG 46 HFC134A 113-9104M

Delphi OIL # 12345923 PAG 150 HFC134A 113-9107M

Delphi PAG RL-488 PAG 150 HFC 134A 113-9107M

Denso ND-OIL 8 PAG 46 HFC 134A 113-9104M Denso ONLY use doubble end capped oil

AC Lubricants – it’s not that simple

Denso DENSO-OIL 6 PAG 46 HFC134A 113-9104M

The Denso-oil6 was used in R12 systems - Must be retrofitted into R134a R12 is illigal

Denso ND-OIL 9 PAG 100 HFC 134A 113-9105M Denso ONLY use doubble end capped oil

Denso ND-OIL 11 POE 80 HFO1234YF 113-0087 Di-electric strength 75kV per 2.5mm

Denso ND-OIL 11 POE 80 HFC 134A 113-0087 Di-electric strength 75kV per 2.5mm

OEM Producer OEM AC

Lubricant ref. Equivalent

Compattible with

Refrigerant Airstal

catalogue ref. Note 1 Note 2

Denso ND-OIL 12 PAG 46YF HFC 134A 113-9108 Denso ONLY use doubble end capped oil

Denso ND-OIL 12 PAG 46YF HFO1234YF 113-9108 Denso ONLY use doubble end capped oil

Doowon ISU205A PAG 46 HFC134A 113-9104M

Hadsys S10X PAG 100 HFC 134A 113-9105M

Hanon Systems FD46XG PAG 46YF HFO1234YF 113-9108

HCC PVE OIL POE 80 HFC134A 113-0087 Di-electric strength 75kV per 2.5mm

HVCC SP-A2 PAG 46YF HFO1234YF 113-0086

HVCC also uses the oil developed by Sanden and in that way they cover both ther mechanical AND electrical range of compressors.

Be sure that the Di-electric strength is acceptable when used in Electric compressors

AC Lubricants – it’s not that simple

Mahle SP-A2 PAG 46YF HFO1234YF 113-0086

Mahle uses oil developed by Sanden This oil has a higher di-electrical strength than normal PAG 46 for R1234yf systems hence it can be used in both mechanical AND electrical compressors

Be sure that the Di-electric strength is acceptable when used in Electric compressors

Matsuhita GU 10 PAG 46 HFC 134A 113-9104M

Mitsubishi PAG 56 / S10X PAG 46 HFC134A 113-9104M

Panasonic DS-83P PAG 46 HFC 134A 113-9104M

Panasonic AE-10 POE 80 HFC134A 113-0087 Di-electric strength 75kV per 2.5mm

OEM Producer OEM AC

Lubricant ref. Equivalent

Compattible with

Refrigerant Airstal

catalogue ref. Note 1 Note 2

Sanden SP-A2 PAG 46YF HFO1234YF 113-0086

Special developped by Sanden PAG 46 with a high Di-electrical strength. For use in Mechanical AND Electrical compressors

Be sure that the Di-electric strength is acceptable when used in Electric compressors

Sanden SP-10 PAG 46 HFC134A 113-9104M

Sanden SP-20 PAG 100 HFC 134A 113-9105M

Sanden PAG 1234 PAG 46YF HFC134A 113-0086

Special developped by Sanden PAG 46 with a high Di-electrical strength. For use in Mechanical AND Electrical compressors

Be sure that the Di-electric strength is acceptable when used in Electric compressors

AC Lubricants – it’s not that simple

Sanden SUNISO-5GS PAG 100 HFC134A 113-9105M

The SUNISO-5GS was used in R12 systems - Must be retrofitted into R134a R12 is illigal

Sanden SE-10Y POE 80 HFC 134A 113-0087

For use in 144 volt systems for Honda. The Di-electrical strength is very important due to the fact that the refrigerant and lubricant are in direct contact with the electrical windings inside the compressor.

Seiko Seiki SK-20 PAG 100 HFC134A 113-9105M

OEM Producer OEM AC

Lubricant ref. Equivalent

Compattible with

Refrigerant Airstal

catalogue ref. Note 1 Note 2

Seiko Seiki DH-150CX PAG 100 HFC134A 113-9105M

The DH-150CX was used in R12 systems - Must be retrofitted into R134a R12 is illigal

Seiko Seiki RS-20 PAG 100 HFC 134A 113-9105M

Valeo ZXL200PG PAG 100 HFC 134A 113-9105M

Valeo VC100YF PAG 46YF HFO 1234YF 113-9108

Valeo VC100YF PAG 46YF HFC 134A 113-9108

Valeo ZXL100PG PAG 46 HFC 134A 113-9104M

Valeo VC200YF PAG 100YF HFO 1234YF 113-9109

Valeo VC200YF PAG 100YF HFC 134A 113-9109

Visteon YN-12B PAG 46 HFC 134A 113-9104M

Visteon YN-12A PAG 46 HFC 134A 113-9104M

Zexel ZXL100PG PAG 46 HFC 134A 113-9104M

AC Lubricants – it’s not that simple

NEVER MIX PAO WITH PAG. IT WILL CREATE PARAFIN, CLOGGING THE CONTROLVALVE AND OTHER NARROW CHANNELS. AND IT WILL ALSO

CAUSE A REDUCTION OF THE LUBRICATION IN THE ENTIRE AC SYSTEM.

Copy right Airstal May 2017