Oil for seals?

[ERIK298]

Hi! Erik here from Sweden, i have an Camry 2.2L from 94. I decided to fix the ac system. New expansionvalve, new condenser, new drier, new seals everywhere (compressor too). Now, i got stuck on what oil to use on the o-ring seals and in the system. Whoever i ask the answer is different, if they have one at all. It says on the compressor to only use ND oil 8. But i read on the internet that i should not use it on the rubber seals, because it is hydroscopic and will form an acid because of contact with air moisture. It will then corrode and damage the seal. Instead i am supposed to use mineral oil for the seals? Not even Toyota service stations could answer this one.

[GM Tech]

I use mineral oil- have for 30 years- with no issues.

[ERIK298]

Thank you for answering, but i have asked several mecanics that tells me to not use mineral oil because of incompatibility with R134a and ND8. The mineral oil will cause layer between the ND8 oil and risk of insufficient lubrication and damage to the compressor. Then when I tell them about the potential damage the ND8 can do to the seal, they give me an answer much like yours. " I have used ND8 on seals in x years and it have never caused a problem." Maybe I can use whatever oil and it will work, but I still wonder what oil I actually am supposed to use? If I dont get an good explanation to this my taught is to use pao oil that is supposed to be compatible with used chemicals in the system and wont form an acid. However the answer to that is either " you are supposed to use mineral" or "you are supposed to use ND-8 oil" or "I dont know". All the people I asked have been so called educated ac system mechanics, weird that I get different answers.

[GM Tech]

I worked for Delphi- the compressor supplier to GM for many years- we always used mineral oil on all o-ring joints and threaded connection- with both R-12 and R134a applications. The assembly plants did likewise. The small amount used would never cause an issue with the integrity of a 134a system. Hardly ever use it anymore, because nearly all connection are sealing washers, which are installed dry. Do what you want, it won't really matter in the end..

[ERIK298]

I worked for Delphi- the compressor supplier to GM for many years- we always used mineral oil on all o-ring joints and threaded connection- with both R-12 and R134a applications. The assembly plants did likewise. The small amount used would never cause an issue with the integrity of a 134a system. Hardly ever use it anymore, because nearly all connection are sealing washers, which are installed dry. Do what you want, it won't really matter in the end..

Thank you