A/C question

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64_Barracuda

64_Barracuda

Virginia Beach VA
FABO Gold Member
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All,
Just got my originial knee knocker A/C system back from Classic Auto Air, they did a great job. The only issue is they sent it back all stock instead of converting the Compressor over to 134, I have been told I need to remove the EPR Valve so it will flow better. I have been told two things, 1) it might not have an EPR valve because it is a bolt on system and 2) It does have one.

But I don't know where it is, I think it is behind the compressor under the great big fitting that is held in by two allen head bolts. Any one have any ideas?

I also have to install a thermostat couple on the evaporator capillary tubes to prevent freezing, which I understand all that. Makes sense to regulate the clutch if there is no vavle to regulate freon flow.

I am excited about the process so far, Classic Auto Air has been great, I will call them when I get home from work about the vavle but I am also polling all my Awesome A Body friends....
 
You mean they left it R-12? WTF???? What are you supposed to do with that? I mean I DO HAVE R12 for myself, but most people don't??

Is this a Chrysler style pump? If so you can refer to a shop manual for the EPR question. If not, a search around the www for whatever it is, York, etc, should resolve the question. I was not aware that any of the aftermarket stuff ever used an EPR. Most of them were not very sophisticated
 
If it's set up for R12, just use one of the "drop in" replacements. (freeze 12 etc.)
 
I would leave it R-12.... R-12 is readily available and will perform WAY better....
 
I will post some pictures. It is totally stock unit, Cool Air unit, it is a knee knocker, divorced from heater, I thought they didn't have EPR valves but got some conflicting info, turns out it doesn't have one, but I will check just in case. No R12 by me, just would go to the 134....
 
The only difference between 12 and 134 is the oil. The temperature/pressure relationship between the two is so close that its a non factor. Shake all the mineral oil out of the compressor and fill it with POE oil and roll with it. OR find somebody with a drum of HotShot and gas 'er up as is. Freeze12 will freeze your balls off if you can get your hands on any, and its a drop in. NAPA used to sell it but last I heard it wasnt available anymore. Honestly, I couldnt tell you how many 12 systems ive topped off with 134 on commercial refrigeration systems. Automotive A/C systems are way more forgiving to moisture and contamination than electrically driven compressors. Pull a vacuum, gas it up, and roll with it.

A side note: If you have a Chyrsler built RV2 compressor, it doesnt matter what kind of oil you use. Those compressors have their own oil sump (and pump) and its basically isolated from the refrigeration cycle, so oil migration isnt an issue. You could literally run Havoline 10w30 in the damn thing if you wanted.
 
I would drain out the mineral oil and install the same amount of PAO 68 oil. It is the latest greatest oil, doesn't absorb moisture like PAG, stays put in the compressor better, and works with all refrigerants and for any specified viscosity. I bought it from Duracool with their refrigerant, but (as stated) it works fine with R-134A since you have your heart set on that. BTW, R-134A is being replaced since it turns out worse for the environment than R-12 (bad greenhouse gas, "ozone hole" apparently wasn't man-made). Duracool calls the oil Ice something, but if you ask it is PAO. You can also buy on ebay.
 
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