Steve wrote:
> Masospaghetti wrote:
>
>> Sorry for three posts in a row. Just got finished under the hood and
>> its been awhile.
>>
>> Napa dude says they will mix fine and that they're actually "the same
>> thing". I have Ester in the system now, its been retrofitted. Its a
>> 1985 Corolla. Only reason i'm asking is because those e-z charge
>> bottles with the press top come with oil in them and only come with
>> PAG. (my system leaks slowly so it'd be more convienent for me)
>>
>> Thanks
>
>
>
> They ARE NOT the same thing. They are chemically different. Ester oil is
> a slightly poorer lubricant than PAG, but PAG is highly reactive with
> any trace of chlorine left over from when the system was running R-12.
> Newer PAG oils labelled "double-end-capped" are chemically stabilized so
> they won't react with chlorine, and are sold as being fully compatible
> with R-12. I'm not sure I trust the chemical stabilization process over
> the long haul, but that's just me. In a retrofitted system, I would
> always gravitate toward sticking with ester oil, simply because I *know*
> it won't break down from chlorine contamination. Even though its not as
> good an oil as PAG I figure non-degraded ester beats the heck out of PAG
> that's turned to brown grittyt mud due to reaction with chlorine
> residues from R-12.
>
> The oils are compatible with each other and both are compatible with
> R-134, so oil circulation won't be the problem. IF there is any problem,
> it will be one of two things- breakdown of the PAG due to reaction with
> chlorine, OR a problem I haven't mentioned yet:
>
> ALL R-134a oils (PAG and POE aka 'ester') are extremely hygroscopic and
> absorb water from the air very quickly. They come with a little water
> already absorbed, no matter how good the packaging. When you open the
> cap to add some oil, they absorb a little humidity before you can close
> it again. Even the "oil charge" cans have traces of water in the oil
> inside absorbed in the factory where its packaged. Every time you add a
> little oil to an R-134a system, you ARE adding a little water. Over time
> continually adding oil to a leaky R-134a system will put in enough water
> to overwhelm the dessicant in the drier, and when that happens acids
> will start forming in the system and you'll ultimately have oil
> breakdown and compressor failure.
>
> Short version: fix the leak.
>
>
>
Thanks for the info.

How will I know when I need to add more oil? I've had to add about 4
ounces of straight refrigerant in the past six months or so but I
haven't added any oil yet.