A/C

1998 BMW 740
100,000 MILES • V8 • 2WD • AUTOMATIC
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FRANXUA1
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Anyone knows what kind of oil conditioner should I use to recharge the A/C system on a 1998 BMW 740i I know I have to use R134 Freon but dont know what type of conditioning oil do I need?

May 11, 2011 at 10:12 PM
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WRENCHTECH
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That system takes PAG 46
May 12, 2011 at 12:04 AM
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FRANXUA1
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can I buy that a any auto parts store??
May 12, 2011 at 1:12 AM
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WRENCHTECH
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You probably should find one that specializes in A/C parts or the dealer. Those discount places probably would even know that there are different viscosities. If they show you a bottle that says both PAG and 46 on it, then fine.
May 12, 2011 at 1:15 AM
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FRANXUA1
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Yea You are right, this past weekend I went to auto zone, and noticed that they do have different viscosity oil, so Im going to go back and check if they have PGA 46, do you know about how much should I put?
May 12, 2011 at 3:04 AM
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WRENCHTECH
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It's PAG not PGA and it depends on how much you lost. It's very difficult to determine. What are you doing to the car?
May 12, 2011 at 10:54 AM
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FRANXUA1
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well I vacuumed it, so I need to refill it...
May 12, 2011 at 2:33 PM
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WRENCHTECH
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Vacuuming a system doesn't remove oil. Sudden blow-offs of refrigerant will remove oil or removing components that contain oil will remove oil but it's still hard to tell how much.
May 12, 2011 at 2:40 PM
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FRANXUA1
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I was told it didnt have oil anymore...
May 12, 2011 at 2:45 PM
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WRENCHTECH
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And why would that be?
May 12, 2011 at 3:09 PM
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FRANXUA1
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I honestly dont know, I was only told that I needed to recharge the oil as well as the freon, cause it didnt have anymore, but there is no leaks in the system..the mechanic said that the system was only filled with air, it didnt have freon or oil anymore
May 12, 2011 at 3:18 PM
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WRENCHTECH
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Refrigerant will totally leak out on it's own and if it happens slowly, it will not take any oil with it. The oil has to be flushed out or the components removed and the oil dumped out, otherwise the oil is still in there. It settles in the bottom of the individual components and mixed with the refrigerant when the system is running. There is no way to know how much oil is left in the system and having too much is just as bad as too little so you need to get some specifics on why he thinks it's empty.
May 12, 2011 at 3:27 PM
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FRANXUA1
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ok Ill do that, I think he said he knew it didn't have oil, cause the compressor wasn't starting
May 12, 2011 at 3:32 PM
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WRENCHTECH
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Compressor working or not tells you nothing about how much oil is in the system. You may be dealing with the wrong guy for this advice.
May 12, 2011 at 3:36 PM
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FRANXUA1
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yea you are right i might just take it to the dealer... what does it mean if the compressor didnt start?
May 12, 2011 at 3:42 PM
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WRENCHTECH
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Could be anything gas or electrical. It needs to be diagnosed properly.
May 12, 2011 at 3:46 PM
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FRANXUA1
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ok thank you, I will most likely take it to the dealer then...
May 12, 2011 at 4:02 PM