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1996 STS
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Discussion Starter #1
I have a 1996 Cadillac Seville 105K miles. My AC wasn't blowing very cold. After some research I determined that my orifice tube was dirty. When I took it out, it was filthy. I put in a replacement and a new accumulator since the system had been opened up. I pulled a vacuum to take any condensation from the system. After I was done, I left the vacuum motor hooked up for a half hour to make sure I didn't have any leaks. After a half hr, the needles were still pegged in the negative, so no leaks. I put some new refrigerant in the car. I didn't completely fill it, but it was ice cold, so I stopped short of completely full. This was in Sept and it was ice cold. After the weather started to cool down, I didn't use it for a few months. When I turned it back on the other day, it said low refrigerant and the compressor had shut off automatically. What could have happened? Could a high or low pressure switch have gone bad after refilling? It's almost like the refrigerant leaked out, but wouldn't a leak have shown up after I pulled a vacuum on the unit? Thanks!
 

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'84 Eldorado and Seville
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1,484 Posts
I would look around joints looking for refrigerant oil leakage. Possibly the joint seals are leaking now (dried out) or the compressor seals are leaking. That would be my guess and first thing to look for.

Usually the accumulator holds some refrigerant oil. Did you replace the same amount of oil with the new accumulator?
 

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1996 STS
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Discussion Starter #3
Thanks, I did not add any oil back to the system. I know the system uses oil, but didn't know the accumulator retained any when removed. Does it hold enough to cause issues if not replenished?
 

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'84 Eldorado and Seville
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Do you still have the old accumulator? If so I would see if it has oil in it and how much. The factory service manual should say how much oil it should have in it (the total system). Depending on how low it is on oil it could burn up the compressor due to lack of lubrication.
If the orifice was clogged oil may not have been circulating and the accumulator may not have had any in it. It could be okay.
Oil circulates with the refrigerant.
 

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2010 DTS
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87,433 Posts
You should drain the component and then replace that amount of oil when changed. I believe the accumulator should be about 3 oz.
Since the orifice tube is what you removed and replaced, my guess is that is where it leaked from.
You might refill and add a dye to locate the leak.

P.S.
The only way the orifice tube would get "dirty" is if the compressor failed (or is failing) and is throwing debris through the system. If that is (or was) the case, then you have to flush all the lines Before you replace the compressor, accumulator and condenser.

EDIT:
Oops, DB2 beat me to it. Didn't mean to repeat what you already said.
 

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1996 STS
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Discussion Starter #6
Thanks to both of you. I do not have the old accumulator. The message I get on my display is ac low refrigerant compressor off, or something along those lines. As indicated by the low miles, she's not a daily driver, so I don't remember exactly what it read. It read the same thing before I replaced the orifice though. As you've both stated, it probably is a leak, just weird that it held pressure after the vacuum and was cold as ice for 7 miles. Doesn't the compressor hold some oil when the system is opened up to change the orifice and accumulator? I don't think the compressor burned up, because I only drove it 7 miles to the house after it was filled and didn't use the ac again until a couple of weeks ago. As long as it's not the evaporator, I'll be happy. I will not raise the body off the motor to replace it.
 

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'84 Eldorado and Seville
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You should drain the component and then replace that amount of oil when changed. I believe the accumulator should be about 3 oz.
Since the orifice tube is what you removed and replaced, my guess is that is where it leaked from.
You might refill and add a dye to locate the leak.

P.S.
The only way the orifice tube would get "dirty" is if the compressor failed (or is failing) and is throwing debris through the system. If that is (or was) the case, then you have to flush all the lines Before you replace the compressor, accumulator and condenser.

EDIT:
Oops, DB2 beat me to it. Didn't mean to repeat what you already said.
It makes me wonder if the orifice is clogged again causing a low refrigerant signal. I don't know where the pressure switch for that system is located.
Probably the compressor is failing. If it's a R4 likely it is.
 

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'84 Eldorado and Seville
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Thanks to both of you. I do not have the old accumulator. The message I get on my display is ac low refrigerant compressor off, or something along those lines. As indicated by the low miles, she's not a daily driver, so I don't remember exactly what it read. It read the same thing before I replaced the orifice though. As you've both stated, it probably is a leak, just weird that it held pressure after the vacuum and was cold as ice for 7 miles. Doesn't the compressor hold some oil when the system is opened up to change the orifice and accumulator? I don't think the compressor burned up, because I only drove it 7 miles to the house after it was filled and didn't use the ac again until a couple of weeks ago. As long as it's not the evaporator, I'll be happy. I will not raise the body off the motor to replace it.
Yes the compressor holds some oil.
Have you put a set of gauges on and checked the pressure?
I'm not sure what to tell you. Maybe pull the orifice again and check it and pull another vacumn.
 

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1996 STS
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Discussion Starter #9
No no, you've been very helpful. I'll check with gauges, pull the orifice, and re vacuum and put some dye in and see where I'm at. I'll be sure to add some oil back too. Thanks again!
 

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92 Fleetwood 2dr cpe - FWD, 96 Seville SLS, 02 Seville
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Had a similar issue with a 91 Celica. Would hold vacuum for 24 hours, but leak down in 90 days. It was a leak on the condensor. Had to use a Freon leak detector to find it.
 

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2010 DTS
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If you pull the orifice tube again and it is full of debris, your compressor is failing and as I mentioned earlier, you'll have to do more than just replace it or it will fail again.
 

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1996 STS
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Discussion Starter #12 (Edited)
Thanks all...Ranger, would the orifice be dirty if I only drove it for 7 miles if the compressor is going bad?
 

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2010 DTS
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:noidea: I guess it would depend on just how bad of shape the compressor is in (if that is the problem). That fine screen on the orifice tube acts like a filter and will catch any debris in the system. The only way to really know is to pull it again and have a look.
 

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2016 Genesis, 2006 DTS, 1931 Model A Ford, 1963 Pontiac LeMans conv., 1972 Ford LTD 429 .
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When in doubt don’t overlook the obvious - your leakdown test doesn’t test the schraeder valves. I restore antique cars and make it a practice to always replace them on anything I am working on. Seeing as how your car is over 20 those valves are very suspect. Also, you should do some reading about servicing an a/c system. If I had your car in for repair, a dirty orifice tube would cause me to flush the system, and replace the compressor, the schraeders, all the seals, and the accumulator. The freon charge would include a leak dye. A deteriorating compressor is likely the cause of the filth. And your not replacing the oil with the correct amount is almost always fatal to any compressor. You split the oil between the compressor and the accumulator when you install your new parts. The type of pag oil you use has several options. I use the latest synthetic that is compatible with the old r-12 as well as the later freons and the non-freon substitutes. Like I said - read up on a/c systems if you are going to fool with them. It will save you from mistakes.
 
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