Refrigerant Lubricant

[jgl1]

Any way of determining which refrigerant oil is present in a converted R134a system?

The shop that did the conversion is no longer in business and the receipt fails to detail the lubricant. Additional components (hoses & R/D) now need to be replaced; which oil should be used to top off - PAG or ester? Or should the compressor be drained, the system flushed and an oil of known identity be installed? Esters supposedly have lower lubricity and are moisture sensitive, where as PAG is sensitive to existing chloride deposits in a retrofitted system. Is PAG preferred? TIA.

[Benzmac]

There is an oil that is synthetic and will mix with almost any oil out there. If it was me, I would use it. BG products named FRIGI QUIET. IT is good oil.

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Benzmac:
Donnie Drummonds
1991 GMC Syclone
ASE CERTIFIED MASTER AUTO TECHNICIAN
SERVICE MANAGER FOR 14 BAY FACILITY
MERCEDES SPECIALIST 8 YRS
PARTNER IN MERCEDESSHOP.COM

[Ted2222]

Donnie,
Do you mean it will mix with any R134 oil or ANY oil, including R12? If it will mix with R12 oil, can it be obtained on the Internet?

Thanks

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Ted
1979 240D
160,000 miles

[be459]

Donnie,

I found FRIGI TECH from the web but not FRIGI QUIET. Where can I buy FRIGI QUIET?

Thank you in advance.

David

[HorizonA]

I did a search on www.hotbot.com. Search words "Frigi Quiet". It will give you the website for it and the other products. Sorry I did'nt bookmark the sight. It also lists their distributors by state.

[stevebfl]

Frigi Quiet is a brand name for the synthetic ester oil and additives that BG chemicals sells.

Syn Ester oil is claimed to work with all other lubricants. Personally I would rather have all one kind. The ability to use Syn Ester with different refrigerants is usually the claim. I am not certain how the different lubricants mix with each other.

The key here is whether they are miscible with each other. The technique for using ester with mineral is to add the required amount of ester and ignor the mineral. This is because the two won't mix and the ester is carried by the 134a.

In the case of Pag and ester I don't know and even though they both will work with 134 if they work together you would put a different amount of oil than if they don't mix.

I would flush and start over.

[mbdoc]

Since both MBUSA (DC) & Nippendenso recommend only PAG oil why go elsewhere?? Most lubes that try to do more than 1 job won't do either job well. There are even various weights of PAG oil for different brands of compressors. ISO 46 is the correct weight for Nippendenso & ISO 150 is for GM compressors. As Steve has said start fresh & use correct weight PAG oil for R134a.

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MERCEDES BENZ MASTER GUILD TECHNICIAN (6 TIMES)
ASE MASTER TECHNICIAN
27 YEARS DEALER M.B. Shopforeman
190E 2.3 ITS RACECAR
1986 190E 16V

[be459]

Thank HorizonA. I found the web site.

I was told that PAG oil is not good for R134a conversion. I should use Ester oil instead. I hope I can find a better retrofit oil than Ester oil. Is Frigi Quiet really better? I cannot get any information from BG's web site.

David

[mbdoc]

Whoever told you that PAG wasn't right for R134a doesn't know very much about A/C systems, as all major manufacturers recommend only PAG oil. & if you can afford buying from MB dealer, PAG is all that you will get with STAR & factory part number.

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MERCEDES BENZ MASTER GUILD TECHNICIAN (6 TIMES)
ASE MASTER TECHNICIAN
27 YEARS DEALER M.B. Shopforeman
190E 2.3 ITS RACECAR
1986 190E 16V

[be459]

I was told that the the best oil, so you stated, for R134a is PAG oil. I would like very much to use it on R134A. But I was also told that if it is for conversion from R12, PAG oil will attack the compressor seal designed for R12 causing leakage later. Ester oil is okay but it is not as good a lubricant as PAG or mineral oil.

Correct me if I am wrong.

David

As I understand, PAG oil is for systems which have never seen R12. Ester is the oil used in converted systems. Steve is bringing forth new information regarding the synthetic, sounds great.

I have understood for quite some time that PAG is ONLY for original R134A systems, if this is not true, I hope someone will straighten me out.

Good luck,

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Larry Bible
'84 Euro 240D, 523K miles
'88 300E 5 Speed
'81 300D Daughter's Car
Over 800,000 miles in
Mercedes automobiles

[fiero4819]

I have a 1991 190e 2.6 that I'll be flushing, evacuating, and recharging with R12. I see a lot of posts about refrigerant oil for R134 conversions, but what's right for my system with R12?

Thanks

[jgl1]

Mineral oil, viscosity 500.

M-B used to supply it under the number 000 989 61 03 10 but it is no longer available. M-B has a spec sheet which list several approved alternatives; one is Suniso 5GS refrigeration oil.