R12 -> R134a 1989 Porsche Kit Questions

[HC3]

Could be my problem, I don't know how to use the internet after using it for 20 years. - I just tried to select the lowest freight.
Please feel free to adjust the freight.

[Tim]

Could be my problem, I don't know how to use the internet after using it for 20 years. - I just tried to select the lowest freight.
Please feel free to adjust the freight.

You may need new glasses then. As This is what was sent on your order.

Sub-Total: $41.79
UPS Ground: $17.05

[HC3]

The current conventional wisdom is not to mix mineral oil and PAG oil.
Do you think the person at Denso is playing a trick of some sort on me by recommending dumping the mineral oil out of the new compressor and filling with PAG 46?
Anyone heard of this?

I'm thinking there are two situations, that are not equivalent:

1 - Putting PAG in a system that has been running R12 with mineral oil. There is still quite a lot of mineral oil in the various components.
2 - Putting PAG in a system that has all new or confirmed clean components except for a small amount of mineral oil remaining in the compressor after emptying it out.

Any comments or links to info. on this?

Thanks.

[HC3]

I found some more info. regarding mixing mineral oil and PAG.
It seems it is OK if there is no more than 1% of mineral oil.

https://www.epatest.com/faq/609/#ET-15
See technical question #13.

I now have a large amount of ester oil (32 fl. oz.) I could use that for multiple flushes of the new Denso compressor filled with mineral oil. Then do a flush or two with DEC PAG 46 and a final fill of DEC PAG 46. How does that sound?

[HC3]

Another question.
When switching over the manifolds from an old compressor to a new compressor (R12 system to R143a system) should the mainifold O-rings be green (HNBR) instead of black?

[Cusser]

Do you think the person at Denso is playing a trick of some sort on me by recommending dumping the mineral oil out of the new compressor and filling with PAG 46?
Anyone heard of this?

I've drained compressors, flushed out the inappropriate type of oil, flushed with type I wanted (twice, 6 oz. each time, rotated compressor center about 10 times), then drained and added appropriate amount of oil.

Not all refrigeration O-rings are green.

[HC3]

Do you think the person at Denso is playing a trick of some sort on me by recommending dumping the mineral oil out of the new compressor and filling with PAG 46?
Anyone heard of this?

I've drained compressors, flushed out the inappropriate type of oil, flushed with type I wanted (twice, 6 oz. each time, rotated compressor center about 10 times), then drained and added appropriate amount of oil.

Not all refrigeration O-rings are green.

That's what you have done and apparently it has worked out. A problem I see, for the aftermarket auto AC industry, is that there are no independent scientific evaluations of the common questions that come up regarding using the various lubrication oils in typical situations. The large companies e.g. Denso does their own testing but the details of these tests are not made public.

Noted not all e.g. R134a compatible O-rings are green. I guess the question could be restated - What is the proper or best O-ring material for R134a fittings? Then the next question would be what material are the O-rings that e.g. came in the box with the Denso R12 pump where R134a will be used? What is the O-ring material in the R12 -> R134a QD adapters?

[HC3]

This paper, talking about O-ring material, appears to come from an independent and reliable source. The company is Four Seasons - I think they are based in Europe and sell a wide range of mobile AC components. This could be a questionable source but the best I could find so far. The Parker O-ring compatibility chart lists Freon 134a and HNBR as not enough data.

http://www.compressorworks.com/Upload/F ... HANGES.PDF

[Tim]

As I stated in the email. It's been 24 years since the ban of R12. Would be very odd to get o-rings that are not compatible with R134a these days.

Nothing wrong with gathering information. But at some point you just need to dig in and get the repair done.

[HC3]

Thanks Tim and Cusser,
It looks like HNBR O-rings come in black or green.
They may not be exactly the same (e.g. different durometer)
https://www.globaloring.com/oring-colors/

I guess I'll assume the QD fittings for R134a will be OK.
It makes sense after all this time at least the R134a fittings should have compatible O-rings.
I might try putting some teflon tape on the threads as a belt and suspenders approach.