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Air Conditioning compressor and R134 Conv.

fltplan

fltplan

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San Diego, CA
Hey guys, my compressor just froze up. I've chased down a couple fan and blower problems related with the relay, but now the compressor froze up completely. I've priced out a new compressor between $200-300, but wanted to know what a fair fee would be to convert to R134 with the compressor install. I'm having this done out of town, so just wanted to be sure before someone yanks my chain. Thanks, Steve

It's for my 90' Blazer.
 
Smert azz.
(Chemically enhanced even!)

Just asking really. I dunno which one the SBC's of the era use. I know the one for the 6.2L diesels isn't known as all that great of a unit and a member on here fabbed up a way to put a different, much better compressor on. Since mine is down I'm probably going that route considering I'm probably starting over from scratch and I have time as it's not my DD anymore.
 
he should have that "pancake" style, i believe it's the r-4 unit, could be the r2d2 unit too though :thinking:

i wouldn't be suprised if you take it to a shop and have them replace the compressor, with the flushing, freon and other misc shop supplies if it costs anywhere from $500-1000.

yeah you priced out the compressor at $200, but ya need to add about 30% to that price for the shop mark-up, plus their labor rate of anywhere between $40-75/hour, probably 2-3 hour job.
 
If he is really really lucky, its an R4, and it died quietly.

That is the only redeeming quality about that compressor.
Its a 4 cylinder compressor with the 4 piston rods pressed lightly into a "scotch block".

There is not much holding the shafts in.
Unlike most compressors, that come all to pieces when they freeze up and put shavings all through the system, the R4 usually has one of the shafts pull out of the block, and not go back into the hole when it comes around again.

Over the years, most of them I saw fail did so when the freon got low. I think if they started to pull a vacuum, it sucked the rod out of the block.
I think I have cut open 8 or 10 over the years, and it was a pulled out shaft every time.

The system will still need to be flushed and the dryer changed along with the orifice if it has one, but hopefully it will not come back to haunt him.
I have seen some of the ones with the destroyed compressors have to have the evaporator, condenser or both replaced because they just could not get all the crap out.
 
if it gets converted to r-134 freon, and hasn't had the condensor replaced recently, it's actually a good idea to do that anyways, with the new 134 condensor the ac system will work much better and especially at lower speeds and idling.


this is just my opinion though :D
 
Just a thought, are you sure it's the compressor and not just the clutch? The clutch can be changed without evacuating the system.
 
okay, sorry about the slow response here. This happened at the begining of my Labor Day weekend on the Colorado River. I drove into Yuma the next morning and realized that you are all correct about having the whole system redone, as these things usually blow parts into the system when they implode. Mine was working great when it just started to squeal, which was the belt slipping, then I turned it off reallly quick. I opted to go back to the river and get it fixed when I got back to San Diego.

I was hoping it was the clutch, but the shop in Yuma said it was the compressor. I don't know how he could tell. other than it stalled the motor when I turned the ac on. Not sure how the clutch works, but it will stall the motor anytime the ac is turned on at an idle. The clutch is much cheaper than replacing the whole system, which I didn't want to do 200 miles from home base. I left the river early this am and didn't have to deal with too much heat without ac. Is there a definitive way to figure out if it's the clutch or compressor. It was working fine and making no noises prior to it stopping (it was working great until it wasn't working anymore).

The model is a Harrisoon model # 3090927/ R-12. Glad it didn't throw a belt when it froze up.
 
OK, just made a quick run out to your place and back from Fl. and peeked under the hood. Definitely the compressor......

Seriously, the clutch freewheels on the compressor, driven at all times by the belt. If the clutch fails, it will either be locked up all the time, or be wobbling and making noise all the time.

While the clutch turns all the time, the compressor only turns when the clutch engages.
Since there is no problem while the clutch is not engaged, its fine. When you engage it, it locks the belt to the compressor.
At which point it stalls the engine.
This means that the compressor is locked up.

Like I mentioned, the r4 is the only compressor I have ever run into that can fail "clean".
Most compressors come apart over a period of time and spew tiny shavings of steel and aluminum all through the system.

An R4 can do that to, but if the piston rod pops out of the scotch block, it seizes on the next revolution, and often there is no metal escaping from the compressor.

You still need to flush the system, change the drier, and the orifice tube.

If you find lots of black crud in the orifice tube, your system has the "black death".

There are several explanations for this.
Some say its a breakdown of the oil that leaches solder out of the coils, others say it comes out of the drier.
I suspect that there may be more than one cause.

If you find that, you need to disconnect all lines, replace the condensor, which you need to do anyway if you are going to 134a, flush out everything you can, replace the compressor, drier, orifice tube, new O rings, new oil, and keep your fingers crossed that you do not have to replace the evaporator.

That black crud just will not flush out, but it will break loose over time and clog everything back up.

Hopefully yours is clean, so normal stuff is all you need to do.

BTW, here is a picture of a R4 compressor.

r4a.jpg
 
Yep, that's the compressor. I will have to check into the black crud, really don't want to spend lots on the ac, as this thing has a new motor and paint in the budget, but not ac.

I was naive thinking I would just go throw a new compressor in and live happily ever after. Did this on a toyota and it worked fine for the couple more years that I owned it. Thanks for all the info. Glad you made it back to FL in time for dinner.
 
Glad you made it back to FL in time for dinner.
Click to expand...

Not a problem, I dipped down in Co and grabbed me a McDonalds........


You might get lucky with this unit. If the compressor froze without coming apart, a simple change of the compressor, drier, and orifice tube might get the job done.

If you can find a reputable shop, they can pump it down, recover the gas, replace the compressor, do the other work, filter the gas and put it back in.

Don't forget Freon 12 is going for between 25 and 40 dollars a pound. And your system has several pounds in it. If you convert to 134a, they ought to at least knock off something if they keep yours.

If you do convert, you really need to replace the condenser. The F12 one just does not do the job with 134a in most cases.
The new gas takes more heat out of the system per pass, and if you don't get rid of it, you don't get cool air.

Big cars, like caddys, town cars, and limos, usually have a big enough condenser to work, but most trucks and smaller cars don't.

If you can stay with 12, you don't have that problem.
 
Openning this back up hopefully.....

89' blazer. If I were to convert to the 134a, would I use the same compressor and dryer as the (f12) system or are they special in someway? Is there a general 134a condensor to use or something more specific?

My clutch is locked up and will not spin at all. Just the outer ring spins so I am assuming my compressor is shot. It also appears to be a re-man unit so I would guess that the potential of metal shavings inside the system would be probable.

Thanks.
 
jeff in co said:
Openning this back up hopefully.....

89' blazer. If I were to convert to the 134a, would I use the same compressor and dryer as the (f12) system or are they special in someway? Is there a general 134a condensor to use or something more specific?

My clutch is locked up and will not spin at all. Just the outer ring spins so I am assuming my compressor is shot. It also appears to be a re-man unit so I would guess that the potential of metal shavings inside the system would be probable.

Thanks.
Click to expand...

You can use all of the same components. Your compressor is likely to be shot and will need to be replaced along with the reciever dryer. Open up all of the lines because you will need to flush the entire system; the evaporator, the lines and the condensor.

The flush can be found at Autozone but after flushing you will need access to an air compressor to blow the flush out of the system.
 
You would be wise to just go ahead and replace the condensor as well, all the new ones are made to accomodate the 134 freon and will work better with that freon than the r-12 designed condensor.

I believe everything you buy for the system is designed now for the 134 freon use unless you order something specific for the r-12.
 
Fordum said:
Don't forget Freon 12 is going for between 25 and 40 dollars a pound. And your system has several pounds in it. If you convert to 134a, they ought to at least knock off something if they keep yours.
Click to expand...

I think R12 is more expensive than that. My cost on it is almost $900 for a 30# cylinder and what do you mean by "they ought to at least knock off something if they keep yours."? If you mean they should discount the price for keeping his old refrigerant then you must not know that it is not legal for them to reuse the refrigerant unless it goes back into the same customers vechicle. Of course I could be wrong about this because I don't work on mobile ac systems but as far as anything else it is a big no no.
 
Do I really need to stick with AC Delco stuff to keep it lasting longer or would reman equipment be OK? It looks like I can get the bulk of the stuff for about $400 at Schucks. Most are "Murray" brand name.

That would be the following items:
Murray Discharge/Suction Line - $56
Murray Dryer/Accumulator - $34
Murray Reman Compressor w/clutch - $140
Murray Orifice tube - $21
Delphi Condenser - $140

If I put all this stuff onto the truck and then brought it in for a leak test and freon fill, could I hit $100 for this extra work for a pro or would it be more?

Just thinking outloud and trying to save some cash. AC is definitely expensive to fix.:eek1:
 
If you mean they should discount the price for keeping his old refrigerant then you must not know that it is not legal for them to reuse the refrigerant unless it goes back into the same customers vehicle. Of course I could be wrong about this because I don't work on mobile ac systems but as far as anything else it is a big no no.
Click to expand...


All the 12 you buy out there now, unless you make a run to Mexico is recycled.
Anyone who opens a system and takes the gas out is required by law to capture it.
Beyond that, things get a little fuzzy.

I have a fairly basic recovery unit. Robinaire I think. Its just a fancy condensing unit.
It lets me suck refrigerant out, condense it to a liquid and pump it into a reusable container.

If I am working on one of my ice machines or something like that, I screw a filter/dryer between the liquid port and the tank.
If the system has never been opened before, thats all I do before I put the gas back in after the repairs.

If you are not going to put the gas back in, there are other options.
The laws have changed from time to time, but I know that a lot of the junkyards have recovery units.
They pull the gas out, and then sell it to a recyclers. The recycler cleans it up, gets any foreign gases out and resells it.

I don't know what a smaller shop does with it. But I suspect it gets sold somehow.

I have not looked lately, but they used to sell recycle units that would test the gas for foreign gas as you collected it, and could get any air out that you might get in.
I don't know if they could do anything about foreign gas or not.

A small shop does not handle the amount of gas necessary to get much money for it, but there are people who will buy it for reprocessing.

For instance: http://www.goldenrefrigerant.com/id20.html

As you can see the pound or two in his truck is not going to net them much.
If it were my personal truck, I would take my equipment down to their shop and recover the gas myself and take it home for use in other equipment.

Jeff obviously does not have that option.
 
I have to pay to dispose of my refrigerant. It's about $40 for a 30# cylinder which is only allowed to hold 24#. If the refrigerant has acid or other contaminats in it, then it cost a chit ton of money to dispose of (I'm thinking $40/lb or somewhere close).

I was thinking that you were thinking that they could sell the gas to the next guy that brought is car in for service which as far as I know is a big no no.

But as I type this and think of the guy in the shop next to mine (auto mechanic), his fancy snap on ac machine basicly recovers the refrigerant into a recovery cylinder, figures out how much it pulled out, if there were noncondensables in it (air, nitrogen, etc.) and then weighs back in the correct amount after evacuating the system. Since he is using the same tank for everybody's vechicle it may be possible that using refrigerant from one car in another is perfectly ok to do in the automotive industry. I know there are two seperate EPA 608 certifications, one is for mobile systems so thats why I don't know the rules on that.
 
Random related thought but there are better compressors you can use than the factory junk. MaxPF has gone into it before. I decided when I rebuild mine this winter/spring/whenever I'm going to upgrade to a better compressor and whatever else he recommended.
 
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