R12 help

[geoshuffert]

I have a 86 944, blk on blk. I without thinking put 134 in r12 system. nothing drastically happened. System was ran , no cold air. I do have a new compressor on hand, but is there anyway I can correct the situation or do I have to redo /replace the whole system?


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[John_AZ]

Replace the receiver dryer.
Flush out the condenser of old oil.
Take compressor out and dump all oil.
Replace all seals.
Replace the oil with Ester oil-put about 6 or 7 ounces directly into compressor and it will flow to other devices.
Vacuum and check for leaks.
Continue to vacuum for 90 minutes to get moisture out of system.
Put in about 30 ounces of R134a.
Cooling will be about 80% +- of R-12 OEM system.

and....
Repeat when you install your new compressor...
J_AZ

[kuehl]

Other than some good details John suggested the issue you might come across is leaks.
The common leaks are compressor seals and original hoses; usually the compressor to condenser line and condenser to drier lines. If you wish to inspect them before starting evac, charge and test, that might save you some frustration. Occasionally you might come across a leaking condenser, visually you might see some oil/dirt residue near the leak. If you want to go 'all the way', you could inspect your evaporator and see if its fins need cleaning; but that can be a project.

[Jfrahm]

I've been using R152A with mineral oil in my 1992 968 with good results. I do not know if just switching to it will alleviate any issues from the R134A and oil incompatibility.

[mattdavis11]

Please don't put all the oil in the compressor, distribute it. 3.5oz in the compressor max. The 10P15 has enough problems with the valve plates, you definitely do not want to slug the compressor right off the bat. Also, rotate the clutch by hand several times after you have the hoses on.

[John_AZ]

Matt is correct on the official policy on refilling oil---especially rotating the compressor pulley several times or more.

I did forget to include "ROTATE THE COMPRESSOR PULLY SEVERAL TIMES!

kuehl--aka Griffiths.com installs many compressors and this is his method:

For AC what is used is a standard "#" (number) size descriptions.
For your year and model you need:
#10 = 2 (evap to comp)
#8 = 3 (comp to cond and 1 under TEV)
#6 = 4 (cond, drier and 1 at TEV)
There are o-rings under pressure switches (depending upon the year) however chances of a leak there are nominal.
The R134a compatible compound HNBR (Hydrogenated Nitrile Butadiene Rubber) or HSN (Highly Saturated Nitrile) can come in an array of colors,
certain o-ring mfg's color code their o-rings (the most common HNBR is green); I've seen blue, green, and black (although black was the OEM NBR).
You will typically find green HNBR.

You could shop around for separate o-rings, you could buy a "R134a kit" for your car or if you just need a reasonable o-ring kit of sorts here is on over at
Pelican

With regard to putting in the refrigerant oil, you do not have to put the oil in each of the components, that is tedious. After the system has run for a few moments the oil gets spread throughout then entire system. There are a few ways to get the total amount needed into the system, for example:
1) Put it all in the compressor, after you connect hose lines to compressor you rotate the outer clutch hub (attached to comp shaft) a dozen times to push it out of the compressor so its not liquid slugged.
2) Pour it in the comp outlet line.
3) If you are having the system professionally evacuated and charged they can inject the correct amount.

SO,

Use the method you are most comfortable with.

Additional Denso info:
http://www.denso.ua/media/27142/denso-compressor-installation-manual.pdf

J_AZ

[Tom944]

I'm sure someone will correct me if I'm wrong but I don't think that you have an issue. The R12 in the system should still distribute the mineral oil. It should not leak since the R12 soaking everything for years should seal the hoses. I would add some Esther oil so that it mixes with the R12 and 134.

[geoshuffert]

Thank you all for your help!


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[kuehl]

Originally Posted by geoshuffert

I do have a new compressor on hand

New compressors tend to be shipped with oil, an unknown qty of oil.
If you use the new compressor, remove the shipping manifold plates. Find a large coffee can. Place the compressor over the can with the open manifold ports pointing into it. Take a socket on a wrench (12 or 13 mm) and turn the nut on the shaft at the clutch several turns (12 is good) in both directions slowly, CW then CCW. Then tilt the compressor on an angle and repeat. Properly dispose of the factory oil and start off with a fresh known quantity; whether you pour it in the ports or you have it injected. If you have a shop service the AC system, let them know if there is or is not any oil in the compressor ; let them know type and quantity. If you are using R12 or R134a refrigerant and you have residual R12 mineral oil in the system (you have not completely flushed the system) best choice is ester. Don't mix PAG in the system or PAG with ester. You can use a 'double end cap PAG' with residual mineral oil however there is no advantage over ester.

[Tom944]

I agree with flushing the compressor. I flushed my new one with Esther oil before installing it since I charged with R12.

[kuehl]

Originally Posted by Tom944

I agree with flushing the compressor.

No "flushing" of compressors.

You can drain, disassemble, clean, reseal, change the oil, but not "flush".