backtothe80s

Hi all,

Back in August, I replaced my A/C compressor, hoses, accumulator, etc on my 1989. Charged with 134A. Worked pretty well. Car sat for the winter. I take it out A month ago and there is NO A/C. My diagnosis leads me to believe that the compressor failed. There may be leaks elsewhere that I haven't found. I injected dye into the system, but haven't spotted anything yet.

I have another compressor coming under warranty.

I was unable to remove the orifice tube. It broke off inside the evaporator tube. Since everything was out. It took all of 10 minutes to remove the evaporator. Using high pressure air, I got the orifice tube to pop out.

Questions:

1. I see no visible dye on the evaporator. Is there a chance it could still have a leak? Maybe somewhere under the insulation? I'm hesitant to put an original evaporator back in. It may be fine. Who knows. It took a lot of air pressure to get the broken orifice tube out. That makes me think it could be ok.

2. There is all kinds of foam and seals all over the original evaporator. It looks like some people here use window sealant for one side. What about the front of the evaporator that's covered with foam? Any way to remove that or is there a replacement? What can I use to remake that?

3. The heat/cool blend door (I think that's what it's called) is visible with the evaporator cover removed. With the head controls on full cold. It's partially open. Based on research here, it's by design. Why on earth would that be? Can I remove the limiter and let the door close completely? I need all the cooling I can get!

paulo57509

If the compressor isn't running, nothing is circulating. Including the dye.

If there's no refrigerant in the system the compressor isn't going to run.

If the system is empty, I would partially fill the system with refrigerant to get the compressor to run to get the dye to circulate. Then do your inspection.

When you removed the orifice tube did you see any black sand like stuff?

Don't forget to add some oil to each component per the FSM before recharging but don't exceed the total amount of oil that's supposed to be in the system. Also, don't run the system with low refrigerant. It needs refrigerant to be able to circulate the oil.

backtothe80s

The system was charged and made to run. The compressor engaged, but there was no cooling. After disassembly, I found the sludged up orifice tube. That's how I determined that the compressor failed.

Please take a look at my questions and see if you can shed any light on them. Thank you.

paulo57509

You never mention why you went through all the part replacements to begin with.

Regardless, as it stands now you have a sludged up system and a new compressor on order. Assuming this is correct, I wouldn't worry about any existing leaks; you're going to be creating many more (but sealing them) in order to make your system right. There are no shortcuts.

Since you have signs of compressor failure (black? sludge) you have to flush and clean the entire system....squeaky clean to get all that crap out. It's much easier to do this with the evaporator and condenser out of the car. You can flush the hard lines with them left in the chassis. Just zip tie cloth rags to the ends to divert the solvent away from the car's finish. I use lacquer thinner and compressed air to move the solvent and dry the innards.

You'll need a new receiver/drier as well as an o-ring kit. Normally, I'd just replace the hose assembly but since yours is fairly new, you can probably get by with flushing it as well.

What is still bothersome is why the second compressor failed. It would be nice to know this so if there was something overlooked it won't happen again. When you remove the compressor, tip it over and measure how much oil comes out.

Can't help you with the foam around the evaporator. There are sources for closed or open cell foam that can be used.

I've never had the heater box opened but I would think that the blend door is cable operated? There should be some kind of cable adjustment, yes?

Use caution and good luck.

backtothe80s

The car had a non-functional system to begin with. Back in August, I replaced the compressor, accumulator, hoses, orifice tube, o-rings, etc. Condenser and evaporator were flushed throughly. Added 6 oz of pag 150 and charged system with 134a to about 80% of R-12 Capacity. All was well.

I doubt my evaporator is leaking, so I'm going to put it back in. No leaks were found using UV light. I'd like to know why I can't close the blend door completely by design. That's my main concern. I will continue to research.

Thanks.

bop11

The pressure cycle switch is the normal freeze protection for the evaporator, keeping the air discharge at ~1°C (33°F) when outside temperature is above 10°C (50°F). Air this cold can cause condensation in other parts of the ducts which is not desirable, causing water problems and mold. The blend door limits minimum temp as follows.

backtothe80s

That's what I thought, but would that be an issue in a climate where summer temperatures regularly reach 110 F?