[330istocknot]

Hello,

My AC compressor just went bad, and everywhere they sale the AC compressor, they sale it alone, however my mechanic says the drier needs to be replaced as the same time? is this true? will it be bad to just replace the compressor alone? let me know! thanks

[Radu328i]

You mean condenser with drier because as much as I know drier element is not suitable for replacement.

[Volasko]

Would you do an oil change and not replace the oil filter? Pretty much the same concept when it comes to refrigerant based systems. I would if possible, I'm just not sure if it is easily accessible.

[simon]

Originally Posted by Volasko

Would you do an oil change and not replace the oil filter? Pretty much the same concept when it comes to refrigerant based systems. I would if possible, I'm just not sure if it is easily accessible.

This is not a correct analogy. The drier element is a desiccant to absorb moisture. It does not filter oil. The drier only needs to be replaced when it has been saturated by moisture and not able to absorb any additional moisture. When replacing the compressor make sure to seal off the lines when not connected to the compressor. Drier replacement is only necessary if lines are left open for 24 hours or more or if you have a refrigerant leak and it drains refrigerant completely. There is no other reason to replace drier unless you have extra time and money you'd like to get rid of.

The drier element is replaceable in cars up to 12/08. After that you need to replace the whole condenser.

Simon

[330istocknot]

Originally Posted by simon

This is not a correct analogy. The drier element is a desiccant to absorb moisture. It does not filter oil. The drier only needs to be replaced when it has been saturated by moisture and not able to absorb any additional moisture. When replacing the compressor make sure to seal off the lines when not connected to the compressor. Drier replacement is only necessary if lines are left open for 24 hours or more or if you have a refrigerant leak and it drains refrigerant completely. There is no other reason to replace drier unless you have extra time and money you'd like to get rid of.

The drier element is replaceable in cars up to 12/08. After that you need to replace the whole condenser.

Simon

The mechanic just mesaged me with $1,400 quote... not something im willing to pay.

I am going to get a used AC compressor and replace it myself. Do you have a DIY for this?


I heard something about replacing oil? and refilling the AC? im so lost with this, is it this difficult? Im a little afraid of doing something wrong. is it just a remove and replace with new AC compressor? etc?

[VWaddict]

On both my Porsche and my VW, I replaced the receiver/drier when each compressor died.

When the compressor dies, it frequently spews tiny metal shavings into the system. A receiver/drier is where these parts are caught. Both times, when I purchased the compressor, the sales document stated specifically that the warranty was null and void if the drier was not also replaced. No exceptions.

Ask the company selling the compressor.

...Now...

As to your "is it difficult" question: If you have to ask, you probably aren't equipped to do the whole job. You'll need a set of gauges, a vacuum pump, a source for the correct freon, and the means to ACCURATELY measure the charge you're putting in (by weight).

On the VW, I swapped the compressor, then drove it directly to a colleague who pulled a vacuum on the system, checked that it was correctly sealed, added the correct amount of the right refrigerant, checked the pressures, and everything worked perfectly. He just didn't want to have anything to do with wrenching on a transverse motor in an absurdly crowded engine bay... "Bring me the car when it's ready to have the freon put in and I'll take it from there, but I ain't f*cking around in them cramped spaces!" was his line.

For the Porsche (which failed a couple of years after the VW), I took it to a proper place. My colleague had retired, and -while I have a set of R12 gauges, and about 8lbs of NOS R12 freon, I took a close look at the job, the older (and slightly brittle-looking) hoses, and just didn't want to mess with it. I paid $1300, and it was WELL worth it.

The VW cost me less than half what the Porsche cost, because I did most of the sweat work myself. I just repaired my home AC myself, and with that I DID set the gas pressure (I have some R22 and a set of R22 gauges) but I don't think I'd do the BMW if it died.

not sure if the BMW uses a receiver/drier arrangement, but I look at it this way: if the compressor supplier REQUIRES you to replace the drier for the warranty... just replace the darned drier.

And if you "heard something about replacing oil" and "refilling the AC?" I would suggest that you may not know enough to take on the job with a high chance of it working reliably for long afterwards...

Also, there's no way on EARTH that I'd ever put a USED compressor into a recently failed system and expect any kind of life-expectancy from it afterwards.

There's enough sweat and curse words to be expended replacing the compressor to make it worth not doing twice... get a new compressor. NOT a used one.

[simon]

Absolutely agree with the above and you should get a new compressor. The new compressor will come with oil in it, this is the amount for a new and empty refrigerant circuit.

VWaddict is also correct. In case of mechanical failure of compressor you can get these little metal chips, or swarf, in the system which is bad. In this case, BMW TIS says to replace:
- compressor
- drier
- line to condenser
- refrigerant oil

Determining the correct amount of oil is tricky. The best way is to flush the system and start from scratch, but this is also difficult or expensive with the right tools. It could be safe to just overfill oil and install the new compressor with all the oil- the con is that the system will not cool as well.

The compressor is difficult to replace because not a lot of clearance. There are three screws holding it. If I remember correctly, one from up top and two from below. You'll have to loosen thermostat to get access to one of them if I remember correctly.

There are the suction and discharge lines as well. Make sure to get new o-rings for those.

You need a refrigerant recovery machine to evacuate refrigerant and will tell you how much oil was taken out as well. When time comes to charge, you need a vacuum pump, manifold gauges, a refrigerant scale, and ideally a drum of refrigerant. Accurate charge must be done by weighing it in and weighing the small cans from auto stores is difficult.

Simon