Ac compressor oil?

bearman

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I would say leave it out. If it wasnt in the new compressor then i wouldn't put it in. I know in some other types compressors the plug is used as a mechanical unloader but don't believe this is the case. Just a thought if that came out of the old one maybe somebody forgot to remove it and thats why the compressor is locked up.
 

JimKueneman

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DO NOT USE BRAKEKLEEN!!!!!!!
What you want is from AC Pro, called clean and flush, Here is a link to it from Oreillys. https://www.oreillyauto.com/detail/...ics-32-ounce-a-c-system-cleaner/cqs11/4384841

Also, the rubber supposedly on R-12 should be replaced as molecule size difference between R-12 and 134a, 134a being smaller, means that it will seep through hoses used on R-12. So, if you don't replace and start losing refrigerant overtime, that could be one of the reasons. Don't for get to use green O-rings as well.

Also make sure the filter screen on the inlet side of the compressor is clean!!!
If he hoses are old the mineral oil has penetrated deep in them and sealed them against the smaller molecule 134a. Use the AC flush on them and pump it down a long time. It should be fine. I have had my original hoses filled with 134a for a year and no slow seepage yet.
 

Sonny

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So to summarize:
-Use AC cleaner only on hoses.
-don’t put old 1” cylinder in new compressor.
-green o rings.
-install be txv valve.
-not sure I know exactly what oil to purchase? “Oil” is different than R134 right?
 

JimKueneman

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So to summarize:
-Use AC cleaner only on hoses.
-don’t put old 1” cylinder in new compressor.
-green o rings.
-install be txv valve.
-not sure I know exactly what oil to purchase? “Oil” is different than R134 right?
Ester is fine for 134a
 

JimKueneman

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I assume you mean the 1” diameter cylinder I pulled out of the old one. I stuck it in the new one. Should I replace it? Clearly I know nothing about this. Just trying to get it assembled for a shop to charge it. Open to any thoughts.
No that is the EPR valve and it is calibrated for R12 pressures. It need to come out or it won’t cool well.

It will have the possibility of freezing up without that part. @bearman recommends a 20 psi cutoff switch in the low side hose schrader valve with a series connection to the clutch and a low pressure set to 24 psi. I have mine set at 34 psi so it is not as cold as it could be but has only started to freez up maybe once or twice.
 

bearman

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Thanks jim for the help.
 

bearman

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Jim gm low pressure cut out switch or call aapack up in phoenix they have some. If you want me to go pick one up i can
 

Grady Cain

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Start stockpiling R134A as most manufacturers have been making the transition to R1234YF which only means that someday, the R134A will get scarce and pricy...
 

bearman

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Yep just got my license to work on the1234 freon. 134a will start by 2021 be gone. The new freon is saleing for 700 plus for 10 pounds. We are going to be screwed as for the class when a new car looses the compressor or if the mechanic tries to flush out the system not going to work. The new condenser the tubes are so small that a tooth pick is bigger so long story short they will replace condenser everytime of compressor failure or flush. Don't get !e wrong the new condenser is way better as far as gas back to liquid and they are claiming a 30 plus drop across it before it hits the txv valve
 

bearman

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Jim need your input its on the heads aluminum who's the best for the price. The shop I'm using to build my motor they say the sleath head from 440 source is a good head but sure reading maybe not your thoughts please
 

idrivemopar

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No that is the EPR valve and it is calibrated for R12 pressures. It need to come out or it won’t cool well.

It will have the possibility of freezing up without that part. @bearman recommends a 20 psi cutoff switch in the low side hose schrader valve with a series connection to the clutch and a low pressure set to 24 psi. I have mine set at 34 psi so it is not as cold as it could be but has only started to freez up maybe once or twice.
Jim, tell me more about using a low pressure cut off switch. I have been using a temperature cutoff switch, but it never allows the air to get cold enough before it cycles the compressor, so I would like a better option.
 

bearman

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Jim, tell me more about using a low pressure cut off switch. I have been using a temperature cutoff switch, but it never allows the air to get cold enough before it cycles the compressor, so I would like a better option.
Yes you can install high and low pressure switches then make the adjustment to your txv valve to et better superheat which will bring down the low side temp now to adjust the superheat i always make sure that the dash controller is set in the middle or at 70 degrees once i reach the temp i am looking for which is 32 to 35 vent temp i then install low and high cut out switches to the coil. Now if ineed it colder i have room to get et it to go colder because i set superheat temp to 32 plus and set my low cut out at 20 degrees now you have wiggle room
 

hyde-park

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Yes. It is the same as my 68 LA.
I've never noticed that before on Chrysler a/c set ups. I was thinking they were only on the high side of the system. Learn something new everyday! Thats why I go to this site daily!
 

bearman

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Interesting photo, there are mufflers on the both the low and high side A/C lines.
Yep in the world i work in they are called ping tanks just a another word for mufflers. But they can collect oil and become a hot or cold spot when tjey get clogged up
 

66chargerpat

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I'm using a low pressure switch from for a mid 80s gm vehicle. These are adjustable and can be found at any parts store.
 

hyde-park

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Yes you can install high and low pressure switches then make the adjustment to your txv valve to et better superheat which will bring down the low side temp now to adjust the superheat i always make sure that the dash controller is set in the middle or at 70 degrees once i reach the temp i am looking for which is 32 to 35 vent temp i then install low and high cut out switches to the coil. Now if ineed it colder i have room to get et it to go colder because i set superheat temp to 32 plus and set my low cut out at 20 degrees now you have wiggle room
Did mine slightly differently. After I removed the EPR valve in my compressor I added an adjustable clutch cycling switch. Mounted it on a brace behind the glove box. Think it had an 18" long capillary tube on that particular model. Drilled a tiny hole (with a rubber grommet) in the ac/ heater box to put it's end in between the fins in the evaporator and wired the under dash a/c clutch wire in series to it. This switch has two adjustments. Cut in and cut out. Stuck a digital thermometer in the center a/c vent and set it at I think 34 degrees cut off and 40 degrees cut in. With a big block I really don't notice much of a RPM drop when it cycles. With a 225-6 probably more so unless there was an idle speed solenoid to up the rpm's when engaged. It doesn't start to get as cool initially as my 93 Taurus, but it gets way colder a short time soon and I'm turning it down to the low fan speed 5 minutes into my 10 minute drive home from work. This link prompted me to remove the EPR valve for improved cooling: https://www.forbbodiesonly.com/moparforum/threads/ac-compressor-oil.147951/page-2
 
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