[Hirnbeiss]

I am no expert, but have been down the road a few times and have acquired the following opinions during these travels:
1. I think it has been shown that the evac machines don’t pull all the oil out of all the components, and
2. It’s better to err on the “more oil” side of the things, just staying under the 100% specs somewhat. The chances of compressor death due to under-lubrication are much higher than the chances due to hydro-lock (assuming you’re careful, and never add more than the total capacity).

 

[Arn]

It's vacuumed and refilled now and blowing cold air. Can't find any leaks with a sniffer or my uv light, so I think it's ok now.

Thank you all so much for the help!

Just saw that one engine mount is leaking but that will be in a new thread.

 

[linuslarsson358]

It's vacuumed and refilled now and blowing cold air. Can't find any leaks with a sniffer or my uv light, so I think it's ok now.

Thank you all so much for the help!

Just saw that one engine mount is leaking but that will be in a new thread.

Is your AC still working as exepected? Did you fill a total amount of 125 ml?

I´m about to replace the compressor on my Passat 3B 1.8T -99. I have the Zexel compressor. My ac-system was working and had no leaks but it didn´t cool the air enough. The workshop diagnosed my car and gave me the advice ro replace compressor, dryer and orifice tube.

The new compressor I bought was prefilled with 180 ml oil. The old compressor had about 80 ml in it. I also got about 15 ml out of the dryer. I called the workshop and asked how much oil I should prefill the compressor with. They answered me that I should keep the same amount of oil that was prefilled in the new compressor. They didn´t even ask how much was in the system before.

Don´t you think this could potentially overfill the system? After all I have read about oil balancing ac-systems I think it would be wiser to refill same amount of oil from the old compressor (lets say 80-85 ml) + 10 % of 250 ml (25-30 ml) for the dryer. Let´s say a total of 115 ml.

Anyone has an opinion in this? It´s almost not worth spending the time and money on the car for replacing the ac-compressor, so of course I don´t want the new one to break cause of wrong amount of oil...

 

[AndreasPassat]

According to the VW bulletins I have read and the Bentley Manual, it states that an OEM replacement a/c compressor is pre-filled with the proper amount of PAG oil.
So if the compressor was removed, the remainder of the system should be vacuumed out to suck out any remaining oil.
Then the new compressor gets installed and then the proper weight of Freon charged into the system.

 

[linuslarsson358]

This is not OEM I guess, if that means bought from VW/Audi? There are compressors from different brands that fit to my model, and some of them are not prefilled, some has a complete system fill and others are filled to 50 %.

I’m a novice and do not have any really knowledge in the field but if you read manuals and look at official instruction videos from example Denso, they say that you fill the new compressor with same amount as you drained the old compressor with. And also that it matters if you replaced other parts than the compressor. They (and different other sources) also say that it depends if the system was completely flushed or only drained from refrigerant. If the system is completely flushed or if you replace all parts, then you would need to fill the compressor with 250 ml in this case.

So I can’t understand the logic in keeping the prefilled amount regardless of circumstances. If the system is completely flushed then 180 ml would not be enough for example.

 

[AndreasPassat]

This is not OEM I guess, if that means bought from VW/Audi? There are compressors from different brands that fit to my model, and some of them are not prefilled, some has a complete system fill and others are filled to 50 %.

I’m a novice and do not have any really knowledge in the field but if you read manuals and look at official instruction videos from example Denso, they say that you fill the new compressor with same amount as you drained the old compressor with. And also that it matters if you replaced other parts than the compressor. They (and different other sources) also say that it depends if the system was completely flushed or only drained from refrigerant. If the system is completely flushed or if you replace all parts, then you would need to fill the compressor with 250 ml in this case.

So I can’t understand the logic in keeping the prefilled amount regardless of circumstances. If the system is completely flushed then 180 ml would not be enough for example.

My post (#24) was not entirely correct. I forgot to add some important information.
I'm sorry about that.

How to explain so I don't make it more confusing...
The entire system is specified to hold 'x' amount of PAG oil. (I don't know what that amount is off the top of my head.)
Each component of the system has a percentage of the total oil in it. The compressor (being the largest percentage of volume), dryer, condenser. (all this info is listed in the Bentely Manual)

So for example, if you replace the compressor but nothing else. The new compressor is 'pre-filled' with the specific percentage of the total PAG oil volume.
In this case the residual oil left in the other components of the system combined with the 'pre-filled' compressor oil equals the total volume needed.
Does that make sense?

Most proper mechanics will tell you that anytime the sealed a/c system is exposed to the outside environment, a full evacuation (vacuum for minimum of 30 minutes) should be done to remove any moisture and all liquids.
Then at that point with a completely empty system, the total system volume of PAG oil is introduced into the system along with the specified weight of Freon.