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Getting my A/C working again.....


07sierra8.1

Question

Ok so first let me give you an insight to what the set up is....

 

The Truck is a 1986 Chevy K20, truck did not come from factory with A/C when the truck was restored, the whole a/c system from a 1981 Chevy K10 was put in my K20 the truck hasn't had the a/c working in about 3-4 years, while my father still had the truck the compressor went bad leaking all the r-12 out slowly till it was all gone. Since then the system has been dry. I have a new compressor and a R134a Retro fit kit.

 

Truck has the R4 "Heavy" Compressor on it

 

Here was my plan, I just wanted to run this by you guys to make sure I am covering all my bases and not going to have to Go back and redo things.

 

1)Add Proper amount of oil to new compressor

2)Reinstall compressor

3)Replace Acuumulator/Drier & Orfice

4)Replace all accessible O-Rings with 134a tolerant ones

5)Pull a vacuum on entire system

6)Recharge System with 134A

 

Now for the questions-

 

Did I miss anything?

What kind of Oil should I use in compressor?

Which port on the compressor does the oil go in?

How much should I add to accumulator/drier?

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Usually the compressor says how much oil to add. I would add oil to the compressor on the "inlet" port. Does your "retro" kit come with a new condenser? R-12 condensers don't provide the heat transfer like parallel flow condensers made for 134a

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no it doesnt :/....and the old compressor says 6oz of oil, and from what I have read on other threads, ester oil works best for vehicles that are retro fit to 134a??

 

Also not sure if this is true or not, but my ex girlfriends father who works at a garage that is commonly known for doing good a/c work told me along time ago to NEVER add any refridgerant with any kind of sealer in it...that over time the sealer gums up and makes components fail?

 

I am asking this cause the retro kit came with 4 cans of 134a with sealer in it..and I was gonna just gonna go buy regular 134a with no sealer instead of using what came in the kit.

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You got some EXCELLENT advice on the sealer. Don't use it .... EVER ... unless your junking the vehicle in a few weeks. The stuff turns to concrete upon prolonged contact with air, rendering every part of your system useless when opened up for repairs. Not to mention clogging thousands of dollars worth of shop equipment ...

 

Here's what I do: Take the new compressor, and FLUSH it out thoroughly with the ester you plan to use, EVEN IF it came tagged that it was full of oil already. Turn it over by hand to pump it out, then fill again until the oil coming out is SPOTLESS. Flush out the lines and evaporator with acetone or brake cleaner, then blow COMPLETELY dry with compressed air. You need the spec for the entire amount of oil for the system - say 8 oz. - then put a couple oz. in the accumulator, 4 oz. in the compressor, then an ounce or so in the condenser. Button everything up, vacuum for 5 minutes, then let it sit for 15 minutes or so and check for leaks, then vac again for at least a half hour - the longer the better. This will boil & remove any moisture that may have been introduced by the compressed air. I've never had a failure doing this in over 10 years.

 

If it were me, I'd have left it R12, as it is a MUCH better refrigerant in so many aspects ... but if that's too spendy ... (I'll probably get excoriated for mentioning this) ... but good ol' CHEAP propane (R290) works even better than R12 if you can believe that one. Not as clean as the pure R290 in Europe, but it works. But since you've already got the conversion kit (o-rings and fittings?) & refrigerant, might as well run with it. Get a parallel-flow condenser as big as you can fit in front of the radiator for 134a.

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Yep, stay away from sealers....

 

dscn1220.jpg

 

 

 

8 oz looks like the amount. I use ester oil with dye. PAG or Ester, whichever you use, keep tightly capped before and after use. They both readily absorb moisture from the air.

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