Oil leak from evaporator case
Thread Starter
Registered User
Joined: Feb 2008
Posts: 11,798
From: Plano, TX
Oil leak from evaporator case
Yep, there has been this slow oil leak which has been dripping for a LONG time, and is still dripping.
There is an "oil return" line that comes from the evaporator but the CSM does not mention it much.
How does this work and why have I not seen this in other AC applications?
The system has refrigerant in it, not sure how much. Is the bottom of the evap always full of oil? Why there and not the compressor?
I assume this oil line is under system pressure and I am almost guessing that much of the oil has leaked out from a break, causing the compressor to be harder to turn as a result.
Recon the compressor is still good if this is true?
The AC once worked, but not well and the compressor gradually got harder to turn, with squealing belts being common.
Trying to figure out if this system is worth repairing or just replace the whole thing and be done with it.
There is an "oil return" line that comes from the evaporator but the CSM does not mention it much.
How does this work and why have I not seen this in other AC applications?
The system has refrigerant in it, not sure how much. Is the bottom of the evap always full of oil? Why there and not the compressor?
I assume this oil line is under system pressure and I am almost guessing that much of the oil has leaked out from a break, causing the compressor to be harder to turn as a result.
Recon the compressor is still good if this is true?
The AC once worked, but not well and the compressor gradually got harder to turn, with squealing belts being common.
Trying to figure out if this system is worth repairing or just replace the whole thing and be done with it.
GM Enthusiast
Joined: Jan 2007
Posts: 3,982
From: Long Island, New York
Always something to do Rob! Hopefully your compressor didn't starve for oil and it still turns freely and quietly. If not, you'll be replacing that too.
I have the same problem with my 71. I am assuming the evaporator has a leak in it and the oil is seeping out from it. My next project too, just waiting for Rock Auto to get them back in stock.
I have the same problem with my 71. I am assuming the evaporator has a leak in it and the oil is seeping out from it. My next project too, just waiting for Rock Auto to get them back in stock.
Connoisseur d'Junque
Joined: Sep 2010
Posts: 21,183
From: The Hudson Valley
There's always a little bit of oil all over the system, a bit more near the bottom than near the top, thanks to gravity, but it's dissolved in the freon and circulates with it.
With the system not used for a period of time, the oil will pool at the low points, and if you've got pressure in the system, it will push the oil out if there's a microscopic hole near the bottom.
If your compressor is hard to turn by hand, you'll need to rebuild or replace it. It should turn fairly easily, like any compressor - smooth, but varying as the pistons compress their cylinders.
- Eric
With the system not used for a period of time, the oil will pool at the low points, and if you've got pressure in the system, it will push the oil out if there's a microscopic hole near the bottom.
If your compressor is hard to turn by hand, you'll need to rebuild or replace it. It should turn fairly easily, like any compressor - smooth, but varying as the pistons compress their cylinders.
- Eric
Registered User
Joined: Nov 2007
Posts: 601
From: Vancouver BC
Oil circulates through the system. Atomizes into fine droplets and is carried with the refrigerant. Remove the compressor and drain the oil. measure how many ounces are left. Compare to OE specification to see how much is missing. If compressor turn by hand, pour in speciffied amount/type of new oil and re-install compressor. Fix evap leak. Evacuate to 700 microns. Re-charge refrigerant to OE specifications.
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