How to clean (flush) a/c compressor 1987 e30 - BMW Forum

ctuck · 06-08-2012, 04:35 PM

When I got the car the a/c was not working and I have purchased a used compressor. I bought some a/c flush, but it says it is not to be used in the compressor. I want to make sure that there is no debris or non-compatible oil inside. How can I clean the inside of the compressor? Also the is minor rust in the a/c lines (metal portion).

Lord Vader · 06-08-2012, 06:47 PM

The one thing i dont mess with is the AC. Please not that the refrigerant inside is oxygen depleting and if you release it in a confined area you could die. Its also under high pressure. Personally i would let a proffesional do it for your safety.

Otherwise, look here: BMW TIS Online Repair Manuals

m20enginebuilder · 06-09-2012, 06:06 PM

There really isnt any way to "flush" out the innards of an AC system. If the compressor doesnt work properly, its probly toast. Also to recharge an AC system isnt as simple as put refrigerant in and go. you MUST draw a vacume on it to at least 25 inches of mercury. Then recharge it, the reason is to remove moisture, because refrigerant reacts with water and becomes very corrosive to ac components like lines and cores, such as the evap core and condenser core. Then itll eat a hole in a line or core and there goes your ac due to there not being refrigerant inside it.

ctuck · 06-09-2012, 07:06 PM

I understand and have the evacuator pump. The new (used) compressor pumps when the clutch is turned. It has been tested. I have no idea what kind of oil was used in it before, thus, that is the reason that I want to clean the inside of the compressor. The old compressor was not connected to the system when I bought the car. The drier was not attached either. I know about recycling refrigerant and pulling a vacuum to remove the moisture. I just need the advice of someone who knows or is familiar with this process of cleaning the inside of the compressors. Thank you for your help.

m20enginebuilder · 06-09-2012, 09:39 PM

Quote:

Originally Posted by ctuck

I understand and have the evacuator pump. The new (used) compressor pumps when the clutch is turned. It has been tested. I have no idea what kind of oil was used in it before, thus, that is the reason that I want to clean the inside of the compressor. The old compressor was not connected to the system when I bought the car. The drier was not attached either. I know about recycling refrigerant and pulling a vacuum to remove the moisture. I just need the advice of someone who knows or is familiar with this process of cleaning the inside of the compressors. Thank you for your help.

Ive taken them apart to clean them, I dont recommend it, but it can be done. Chances are it probly ran the proper oil for it, so itll be fine. Also those systems are desighned for R-12. So your gonna have to obtain some for it.

rockwell23 · 06-13-2012, 11:46 AM

I would flush it with oil by hand.
As long as you don't see any black crap in there you should be ok.

Also Check the clutch before you mount it.
If you do use oil, make sure it's compatible with the type of freon you will be using as they do not all play well together. Same goes for the seals in the compressor itself. There's a list somewhere that will tell you which compressors will tolerate which refrigerants without the seals breaking down.

m20enginebuilder · 06-13-2012, 01:02 PM

Quote:

Originally Posted by rockwell23

I would flush it with oil by hand.
As long as you don't see any black crap in there you should be ok.

Also Check the clutch before you mount it.
If you do use oil, make sure it's compatible with the type of freon you will be using as they do not all play well together. Same goes for the seals in the compressor itself. There's a list somewhere that will tell you which compressors will tolerate which refrigerants without the seals breaking down.

Im gonna say these older e30 type ac compressors require R12 refrigerant, otherwise itll mess up the seals if you put 134a into it