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Discussion Starter · #1 ·
I have ordered replacement parts for my A/C system including dryer, compressor and hoses. The question I have is whether I can disassemble everything now, plug the hoses so moisture does not enter and install new parts when they arrive. Basically, am I risking anything by removing underhood A/C components and plugging the hoses? Seems to me no. Thanks in advance
 

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Last summer I had to replace my condenser because of a huge hole in it so I had my a/c completely apart. I ordered a new condenser and dryer from rockauto and an o-ring kit from bavauto or autohauz (can't remember which.) I didn't take my system apart until I had all the parts. Moisture isn't the main concern once the system is open, it is dust and dirt. These will plug your expansion valve and shorten the life of the compressor. I wouldn't open anything until you can finish the work. Once everything is back together, pulling a vacuum will remove any moisture. I flushed every thing I could with an a/c flush kit and changed every o-ring in the system (except the evap pressure switch, under the dash and didn't want to mess with it) including the expansion valve o-rings which only the dealer had. When everything was back together I pulled a vacuum (harbour freight has both the pump and the manifold gauges for cheap) and it held overnight so no leaks. I then recharged and it has worked great for the past year. A couple of hints, mine is a 2003 325i and the compressor was a Nippondenso (japanese). The oil to use is PAG 46. Dump half the oil into the compressor and spin it a few times and the other half into the lines. I can't remember the capacity but I might be able to find it again. Hope I was helpful. Any other questions I'll try to check back on again. Remember, legally you have to have the system professionally evacuated if there is still refrigerant in the system.
 

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Discussion Starter · #3 ·
How did you flush the system with the flush kit. I do have flush fluid but unsure of how to introduce it into the system and suck it back out. The new compressor I ordered has PEG oil already installed. You said you dumped the other half of PEG oil into the lines. Which lines (compressor to condensor, compressor to dryer, ??). thanks in advance
 

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Amazon has bottle flush kits that hook up to an air compressor. I flushed the evaporator, expansion valve and all the lines with the flush fluid (condenser was new) and then blew them with just air. This removed all the old oil and junk from the system so I had to replace all the oil up to capacity. The only real hard part was removing the expansion valve b/c you have to get in by the firewall. My brother is a tech at a Lincoln dealership and told me they never bother with flushing the system because it is too time consuming. He says when they change parts they just dump a few oz. of oil in the lines/evap/condenser to make up for what might be lost. They don't measure anything. In your case you must consider you lost some PAG oil in the lines you removed. If you choose not to flush the evap and conderser there is still some oil left in those components. Pulling a vacuum will remove some oil but not all. If I were you I would put 3-4 oz. of additional oil in the lines when you install them. Remember when the compressor starts to run the oil will be distributed throughout the system. The main thing is not to dry start the compressor which you don't have to worry about if the oil is already installed. Once together pull vacuum and release two or three times and then let it sit for a few hours with vacuum and see if the gauge drops (my system held vacuum overnight). If vacuum holds then charge using a highside-lowside temp/pressure chart. The book says to charge by weight b/c we have a variable output compressor but I don't have the equipment for that so I charged by pressure and it works fine. Good luck.
 
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