A/C compressor question
 

I rebuilt the compressor with all new seals and gaskets as instructed by the tech article in this website. Stock R12 A/C blows adequately (about 42 deg F).

I noticed that there now is a large black oil line on the inside of the rear decklid.

I've read somewhere that this is expected for this type of compressor; something about the carbon seal naturally letting this happen. And from that, naturally letting the R12 escape slowly. But this is why I rebuilt it in the first place.

Question: is this really to be expected or is the compressor failing again? It's only been about 2-3 months since I rebuilt it.

Thanks.

From what I read it seems few rebuilds seem to last. The supply of new compressors is pretty much gone. Factory rebuilds from Denso are out there but rather spendy. I would not personally buy anything that is not a Denso rebuild.

That black ring is a sure sign your seal is leaking.

After successfully resealing literally hundreds of the 10P15C, I can suggest a few items to go back and review: the nose bore ID, the shaft's OD, felt absorbent wick, high side pressure. There are basically two manufacturers who distribute the repair components through the U.S. to resellers. I've seen errors in o-ring sizes, problems with quality control and so forth; for example, the wrong size o-ring supplied for the O.D. of the steel race for the shaft nose seal assembly will quickly lead to a leak. The “black” in the oil line on the deck lid can be from either: residual contamination in the refrigerant loop, carbon black from the drive belt or collected particles in the clutch. Provide you handled the carbon bearing in the nose seal properly it should last a long time. Occasionally you will come across a compressor that no matter how well the components appear to be “in spec”, and no matter how meticulous you are with the procedures..... it just comes back to haunt you (Nip’s and Sanden’s both)

Before you recharged, did the vacuum hold for more than 20+ minutes at -30 atmosphere on the guage?

I understand this procedure is a must for any AC repair be it R12 or R134.

I too read that R12 systems are designed to leak out ( remarkable ).

Switched to ES12 industrial, the molicules are larger and resists leakage.

No system is "designed to leak".

A stock 911 or 930 simply has more linear footage of non-barrier hose as compared to other makes of vehicles with front engines which by design have less.