A/C compressor

I got mine from Autozone, about $200 rebuilt. It has been in truck for about 8-9 years now. I have converted to R134 last year.

A good time to convert to R134 w/Schrader valves Probably many used compessors an be used if they handle the head pressure. You can change the v belt pulley if you have a compatable shaft, and make sure the RPMs remain the same due to the diesel turning less RPMs than a gas engine. I plan to put a VW compressor on my 390 with an aftermarket A/C setup.

Go for the new one if you can afford it. Autozone is the only place I know of to get new compressors at a reasonable price.

autozone/other

Autozone sells factory seconds. Their stuff is reject crap that the OEMs don't want to sell because of warranty concerns. So they sell it to Autozone for very cheap with an agreement that Autozone will handle all the warranty in house.

AutoZone is a competitor of ours. If this were true I'd be all over it. I don't know what brand they offer, no parts store can afford to sell sub-standard compressors. There are plenty of "warranty" issues already, with people screwing up the install. If they sold junk compressors the comeback rate would cost them dearly.

Rex in Fort Worth

Agreed. :)

I looked it up and a York was $249 or $259(?) and I called a local supplier and they wanted $279. I told them the price at AutoZone and asked about bringing in my sales tax license for "dealer" prices and they dropped it to $222 plus tax ...that I paid right then.

He also said the AutoZone compressors were made by X (don't remember, didn't catch it) and theirs were made by CCI (Climate Control Inc) and is a better unit. It was cheaper so i got it anyway. :)

What do you think? Is what he said true you suppose? Not that it matters either way but if you know one way or another that would be cool for me to know too. :)

Also I have a question that would help me big-time, it would break up the log jam I have in my brain, better than setting off dynamite in my brain maybe? ;)

I've been studying A/C on my own and want something specific as to why R-22 won't work in a R-12 system. The scientific answer would help me out I'm sure. It's a symtom of not having a teacher, I run into that alot when studying things on my own. :/

I bought some used R-12 gauges from a used tool store (Kent's Tools) for

On Sun, 31 Aug 2003 03:00:52 +0000, alvin rearranged some electrons to form:

Yeah, I think so. I'm not an expert. :-( The liquification comes when the latent heat in the compressed gas is removed via the condenesor coil, and the gas condenses into a liquid. R-22 has a higher pressure at a given temperature than R-12 does.

It also means that an evaproator with R-22 will run a lot colder (at the same pressures) than R-12, which is why they use it in freezers.

One other note... R-12 is not manufactured anymore, so it is extremely expensive. R-22 is supposed to be phased out in the next 10-15 years, I think.

I didn't really pay attention during those mechanical engineering classes...electrical engineering is my background, so your mileage may vary.

You got me all curious and I looked at my recent Autozone purchase. It's a Four Seasons, made in USA, and not the original brand that was on my car. $300 with clutch for my Chrysler LHS. Papers from "Temperature Control Division" (of autozone?) also refer to Murray and Everco, neither of which I have heard of. I missed part of your post, so I'm curious where you bought the CCI compressor. I would guess the Autozone unit would have been one of the 3 brands listed here.

I'm a chemical engineer and I will give you a longer answer. The reason is not science. It's purely a practical answer, but it's based on thermodynamics. As another poster said, R-22 runs higher pressures to produce the same temperatures as R-12 (R-22 is "easier to boil and harder to condense"). The air conditioner is thermodynamically very simple, and it could be designed to run on R-22, but it's not. There are two things to consider here:

1. Your car is designed to prevent freezing on the evaporator. Most cars have pressure controls in the low pressure part of the system. If these controls, set for R-12, work, the compressor will probably not build enough pressure to condense anything on the high side. If it did, your evaporator would freeze. This would be simple to fix, of course, from an engineering point of view. You could jack up the suction side to 60 psig and everything is fine. If your car controls its evaporator temperature and not its pressure, you'd never even see this one.
2. Higher discharge pressure required to liquify R-22 would also require higher differential pressure and would have to be considered in the design of the compressor seal, all the force-bearing parts of the compressor itself, all the pressure-containing components of the system, the clutch, the belt drive, and the restriction orifice. I haven't tried this, so I don't claim superior knowledge of what fails first if you actually try it. The hoses and the seal would be my guess. Obviously there's no easy way to modify an R-12 system to run at high pressure, but a system designed from scratch to run on R-22 would be no problem. Rubber hoses would probably be the worst part of the system to design, but could be replaced with flexible piping for instance. I don't work in the auto industry so I don't know why they never used it, but it would be slightly more dangerous to work with. That's my guess.

Bear in mind this is an engineering answer and it is really only dealing with the thermodynamics and difficulties of designing components for this environment. I am not adressing everybody's experience but rather the underlying principles.

Two other thoughts:

Traditional R-22 with a canned electric motor will work in a mobile setting, and you'll see that on top of every camper or motor home. The reason we don't use that used for car air conditioning is the amount of electricity needed to drive the motor would be a real pain to generate in the space available under the hood.

I like aircondition.com as a good place to get in a discussion group with people who really know auto air conditioning. Also, I would encourage you to get certified to buy refrigerants and try out some of the R-12 replacements that are on the market. It's very easy (the test I mean). You'll find there that R-22 mixed with other things TO MAKE IT EASIER TO CONDENSE is actually a pretty good solution and there are some R-12 replacements concocted that way. Which may actually be another answer to your question.

|> Agreed. :) |>

|> I looked it up and a York was $249 or $259(?) and I called a local |> supplier and they wanted $279. I told them the price at AutoZone |> and asked about bringing in my sales tax license for "dealer" prices |> and they dropped it to $222 plus tax ...that I paid right then. |>

|> He also said the AutoZone compressors were made by X (don't |> remember, didn't catch it) and theirs were made by CCI (Climate |> Control Inc) and is a better unit. It was cheaper so i got it |> anyway. :)

I'm not familiar with CCI. Every major region has a regional compressor rebuilder. They all use the same parts from the same suppliers, most of them here in Fort Worth last I checked. If yours was an older York 2-cylinder compressor, any competent rebuilder should be able to make one as good as a new one. Those are easy.

|You got me all curious and I looked at my recent Autozone purchase. It's a |Four Seasons, made in USA, and not the original brand that was on my car. |$300 with clutch for my Chrysler LHS. Papers from "Temperature Control |Division" (of autozone?) also refer to Murray and Everco, neither of which I |have heard of.

Four Seasons is the 500-pound gorilla of the Auto A/C aftermarket. They have bought out and assimilated Everco and Murray, both of which were giants in their day. I'm sure the documentation was cover the transition period when you could have bought any of the three, depending on wwhat was on the shelf. All 3 were of equal quality.

Rex in Fort Worth