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Help Needed with an Atypical AC Problem

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Old 06-05-2013, 08:21 PM
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Help Needed with an Atypical AC Problem

Well, I just spent the last several days replacing the AC compressor on my 81 380sl. However, when I pulled a vacuum, I mistakenly left the vacuum pump on with the manifold gauges open, which ended up sucking vacuum pump oil into the system.

Although I'm not sure how much oil got sucked in, it took app 150 cc of oil to bring the level in the pump back up to where it was before the oil got sucked up. So, now I'm wondering which of the following is my best option:

1) Run the AC and hope that the pump oil won't damage anything;
2) Take the system apart again, remove the compressor, replace the oil in it, and flush the hoses, considering the time and effort that doing this will require;
3) Try to remove the oil some other way;
4) None of the above.

Thanks in advance for any advice anyone can give me.

Bill
Old 06-06-2013, 12:08 PM
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Answer

If the compressor and system where totally dry 170 CC is the full oil load.

If the system sucked air/oil through the vacuum pump, you are in a rough spot.

When you vacuum the system again, some of the oil will come out, and you will be estimating (guessing) what the total is.
You risk burning out the compressor due to under fill, or loosing refrigerant capacity to excess oil.

The only accurate procedure is to start again:
* Drain the compressor
* Replace the receiver - dryer again
* Flush all other components

The final decision will be up to you.

whunter@pelicanparts.com

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Old 06-07-2013, 11:49 AM
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Originally Posted by PelicanParts.com
If the compressor and system where totally dry 170 CC is the full oil load.

If the system sucked air/oil through the vacuum pump, you are in a rough spot.

When you vacuum the system again, some of the oil will come out, and you will be estimating (guessing) what the total is.
You risk burning out the compressor due to under fill, or loosing refrigerant capacity to excess oil.

The only accurate procedure is to start again:
* Drain the compressor
* Replace the receiver - dryer again
* Flush all other components

The final decision will be up to you.

whunter@pelicanparts.com

.
Thanks for the advice, Mr. Hunter, even though I was hoping to hear something else. But I guess that's going to be the best way to correct my mistake.

As for the amount of oil that's needed to lubricate the new compressor, the 107 manual says to add 200cc, or 300 cc if the system was flushed, which I suppose I should do. So, even though the original refrigerant was R-12, I'm assuming that I will have to add 300cc of oil even though my system was converted to R134?

Bill
Old 06-08-2013, 07:22 PM
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I don't want to belabor this thread. But I just recalculated the amount of vacuum oil that entered my system, and it's less than 100 c.c.. So, I was wondering whether that changes the situation any, as I obviously don't want to have to take the system apart if I don't have to.

I was also wondering 1) how far that oil would have gotten pulled into the system, considering that I didn't run it, and 2) what the possible and probable downsides would be if I do run it with the vacuum oil in it.

Thanks in advance for the advice, guys, as this is the first time I've dealt with something like this

Bill

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