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Discussion Starter · #1 ·
No Posts on AC systems and It's been a hot summer here in the south. I was just wondering who's still running R12 beside me?

My system was not preforming up to speed on a couple of 95-101 degree days so I thought I'd investigate. I had a local shop recover my R12 and pulled the evaporator and checked the expansion tube.

The expansion tube was pretty clean but had some black residue (kind of like powder coating very thin) which I think are the old hoses shedding some interior rubber, so new hoses are on order. The evaporator box had some rubber strips missing allowing some air to bypass the evaporator, must have been left out during the previous owners trip to the stealer-ship since he had work done just prior to my purchase, that was 12 years and 120K miles ago!

I'm putting the evap box in today and the hoses will be here in a couple of days. Next week when I get the shop to put my R12 back in I'll post a report. The shop is only charging $50 to recover and replace the R12, I think that's a fair price!!.
 

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I still have R-12, and like you I'm due for a charge. The A/C isn't getting as cold as it should. Without looking in my log I'd say it's been about 8 or 9 years since I had mine charged and then R-12 was still legal here in WY. Don't know if it still is, I meant to call a shop the other day.
Speaking of price, I used to charge a few on heavy trucks so I know what's involved. Back when I had mine charged last I phoned my friendly Ford dealer to get a price knowing the price of Freon and the fact mine would only take a small amount. They quoted me $240. I phoned the Chevy dealer and said excuse my bad language but I have a Ford F250 and would like a price. He said right around $75, I B.S.'ed with the service manager (nice guy) while it was being charged and when I paid the bill it was only $64!
 

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Discussion Starter · #3 ·
My system was not low of Freon as a matter of fact I'd added a little hoping to cure the problem so it was a bit overcharged. The $50 is for R&R only but since I won't need all that was removed there will be no addition charges when he recharges it.

I replaced my compressor three years ago (only 20K miles) so I'm not doing anything with it. I'll replaced the receiver/dryer of course and the hoses and new o-rings.

Resealing the box and adding some additional insulation/heat shield plus cleaning all the cat/dog fur/crud out of the evaporator core will help a lot. I'm adding a heater hose bypass valve and will tighten up the cable to the bypass door which should have my system back to full efficiency.

My experience will auto/aircraft Freon systems is that you must address the whole system, it's less expensive to fix all the problems at once than doing it piecemeal. Quick fixes are usually temporary fixes.

I hope to see my wife wrapped up in her blanket again soon!
 

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I am not on R12 anymore I couldn't find any one that had some R12 left to put in int with out charging me a arm and leg so I just had them pull the R12 out and one day at work I put clean new R134a in it and its been doing great the only problem I seam to have is when I am idling for a while some times it just doesn't cool the truck until I start moving again and then it gets good and cold
 

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Discussion Starter · #5 ·
I am not on R12 anymore I couldn't find any one that had some R12 left to put in int with out charging me a arm and leg so I just had them pull the R12 out and one day at work I put clean new R134a in it and its been doing great the only problem I seam to have is when I am idling for a while some times it just doesn't cool the truck until I start moving again and then it gets good and cold
Yep the low cooling at idle is a problem. To correct that some switch to a parallel flow condenser with added electrical fans. I figure just buy the R12 and keep it original.

My recovered R12 will be re-installed in the morning hopefully with the other work I've done it will bring my system back to new specs. :)
 

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I've never done much A/C work except charge a few in the distant past, but don't you have to change a minor part or two, evacuate the system and use a different oil when switching over from R12? Can't remember the name of the part, but it's in one of the lines.
 

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There is an oil you can use when switching that is compatible with both refrigerants.

The part your thinking of is probably the orifice tube.
 

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R-12 uses mineral oil as a lubricant. Most, maybe all, OE R-134a systems use PAG oil for lubrication. For R-12 to R-134a retrofits, you can use PAG or POE oil as a lubricant. POE would be the better choice if you had some residual mineral oil left in the system.

You also need to change the clutch cycling switch. R-134a needs to open the clutch circuit at a slightly lower pressure than R-12.
 

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Good information, thanks. And orifice tube is what I was trying to remember, Chuckster.
 

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Discussion Starter · #10 ·
Just charged my system with the recovered R12 and cooling is great. Thirty nine degrees out of the center vent. New: Murray Compressor from O'Reillys (not rebuilt) with clutch, receiver/dryer, hoses, expansion tube, seals. 10 ozs of mineral oil after flushing all lines. Pulled the evaporator and cleaned. Installed heater core shutoff vacuum operated at max cool only.

I used the mineral oil after considering Universal PAG or PAG 46 Ultra (double end capped) both of which being OK for R12. The double end capped being by far the best, however it is expensive and no one had it locally. Read Service Issues Using Ultra PAG 46 would have been advantageous if I later wanted to convert to 134a but that's not likely.

I spent about $400.00 including having the R12 recovered and reinstalled. My time and labor excluded. R12 RULES. as for the hole in the ozone layer I think the demise of R12 had more to do with Dupont's patent running out making a big hole in their profits.
 

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Yep the low cooling at idle is a problem. To correct that some switch to a parallel flow condenser with added electrical fans. I figure just buy the R12 and keep it original.

My recovered R12 will be re-installed in the morning hopefully with the other work I've done it will bring my system back to new specs. :)
I was planing on dueing that this summer but never got around to doing it
 
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