Automotive Air Conditioning Information Forum (Archives)

mrdap on Mon July 25, 2011 12:16 AM

Year: 1967
Make: Chevrolet
Model: Impala
Engine Size: 396
Refrigerant Type: R12 or R134
Ambient Temp: 100
Pressure Low: TBD
Pressure High: TBD
Country of Origin: United States

Hello,

I have just acquired a 1967 Chevrolet Impala with factory AC (Reman A6 compressor). This vehicle has some of the most unusual adapter fittings on it, so I do not know what refridgerent or oil is in it. There are no notes or tags indicating R134, so I think it has R12. But here are pictures of the fittings:

Low Pressure
Hi Pressure

The first picture, low pressure, threads are regular (RH tighten) diameter is .5 in
The second picture, hi pressure, threads are left handed (LH tighten) diameter is .432 in.

The LP fitting had a blue cap, HP fitting had a red cap, but it has a left hand thread.

I am guessing that somebody may have been trying to use some kind of old guage set and may have attached these adapters, but I don't know.

At any rate, there is some pressure left, but I intend to remove the adapters, purge, install a new drier, evaluate and recharge. I want to know what kind of oil is in it.

Is there a simple way to determine what kind of oil is in the system?

I have a lot of equipment, vacuum pump, electronic scale, electronic leak detector, gauges, R12 and R134 drums, etc., but I do not have a gas analyzer.

Thanks in advance.

TRB on Mon July 25, 2011 12:43 AM

Those could be Commercial R134a adapters, HVAC industry. As for the oil question. I've never seen a oil test strip.

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bohica2xo on Mon July 25, 2011 2:41 AM

Your system contains some substandard junk refrigerant, and the oil in the system should be flushed out to start over.

There is a list of "unique fittings" HERE Figure out which fittings you have, and you may know what was pumped into it.

When working on an unknown system with an obvious re-fit like that it is best to just flush & start from bare metal.

B.

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"Among the many misdeeds of the British rule in India, history will look upon the act of depriving a whole nation of arms, as the blackest."
~ Mahatma Gandhi, Gandhi, An Autobiography, M. K. Gandhi, page 446.

JJM on Mon July 25, 2011 11:43 PM

Yup, Bohica hit the nail on the head... depending on TPI (Threads Per Inch), with a left hand high side fitting you probably have R-406A or R-414A (AutoFrost).

At least it appears someone did a proper retro with the correct fittings.

Joe

When considering your next auto A/C purchase, please consider the site that supports you: www.ACKits.com

Cussboy on Tue July 26, 2011 1:04 AM

Quote
Originally posted by: mrdap Is there a simple way to determine what kind of oil is in the system?

If you work in a chemistry lab like I do, infrared spectroscopy can readily differentiate between "mineral-type" oil used with R-12 and polyethylene glycol or ester type oils.

I've done such only twice, and one rebuilt compressor had ester-type and one had mineral-type. So the first was flushed with mineral-type, then filled with same to use it with R-12.



Edited: Tue July 26, 2011 at 1:04 AM by Cussboy