Automotive Air Conditioning Information Forum

I have a 92 Cavalier with the 2.2L which uses the V5 compressor. almost two years ago I replaced the compressor with a new one due to it leaking at the body seal and it had been on the car since about 2007.

Fast forward to about a month ago and I have no air. I check things out and discover that there is a leak at the back of the compressor and it looks like it's coming from where the lines go into the back of the compressor.

Since the system is empty I remove the lines and install new sealing washers. I make sure that the securing bolt is tight. I vacuum the system down for 30 minutes and then let it sit for 30 minutes and the needle on the vacuum gauge does not move. I then vacuum the system down for another 30 minutes and then let it sit again for 30 minutes and the gauge still doesn't move so I was convinced that I had no leak. Since I still have a tank of R12 and that is what was in it, I recharge the system with the correct 36 oz and get 38 degrees from the vents.

Today I run my hand on the back of the compressor just to check and it comes back soaked with oil. The air is still Ice cold. I put the car up on ramps and it looks like it's leaking at the line going into the back of the compressor again. It looks like it's leaking at the upper line which is the cold line. The lines above the connection point all look dry so I don't think the line is cracked and like I said, the air is still ice cold.

I'm pretty frustrated because I don't know how it could be still be leaking and really don't know where to go from here. I'm pretty sure it has the correct sealing washers because they look the same as the ones I just removed and from the ones I kept from the 2007 compressor replacement.

Does anyone have any suggestions? Thanks.

Hard to tell remotely. It could be corrosion on the mating surfaces of the compressor, the line flange, or both, preventing the sealing rings from seating properly. Maybe the line flange is bent a little from a previously over-tightened bolt, causing a slow leak, or even a bit of debris on the mating surfaces. One thing's for sure: If you have oil leaking out now, it won't be long before the refrigerant leaks out, too.

Incidentally, sometimes a system will hold vacuum but leak under positive pressure.

I would recover the charge (or have it recovered), clean everything off, and examine the parts closely for any defects. If you find none, reassemble everything with new sealing rings, coating all the mating surfaces with Nylog to ensure the best possible seal, evacuate, and recharge.

I forgot to mention that since you've had the system open to the atmosphere a couple of times already, now would be a good time to replace the accumulator, adding about one ounce of mineral oil to it before buttoning everything up.

That compressor is mounted low on the engine. Any chance it is not refrigeration oil?

Generally an oil leak loses refrigerant as well. You say it still cools well. Did you happen to put dye in the oil charge when you put it back together?

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As far as I know, the AC manifold lines are original to the car and it's possible they could be bent at the compressor. I ordered a new set of lines which I have already received but I won't get a chance to work on it for a couple of weeks since I will be on vacation. The mating surface of the manifold and compressor did not look corroded when I replaced the sealing washers so I don't think it's that.

I'm pretty positive it's refrigerant oil since there doesn't appear to be any fluid in the area above the suction port on the compressor.

I don't see any signs of dye so I don't think I put any in on the compressor and accumulator replacement from two years ago.

I do have Nylog but was always told to not use it on the sealing washers, only the O-rings so I have not used it on the washers.

I just want to make sure I fix this right this time because I don't want to waste any more R12. Thanks for the suggestions

Well, the AC finally quit so I will be replacing the lines after I get back from vacation. Still deciding if I should replace the compressor too.

You're close to 30 years on this guy. Spend it.

I don't have a problem spending the money, I just hate wasting it.

I finally got the lines replaced on the Cavalier but didn't have time to re-charge the system so I may do it tomorrow. I'm still not sure if the new lines are seated correctly at the compressor. They seemed to rock slightly when I was just holding the end to the back of the compressor but of coarse the sealing washers probably were not fully seated. I did not see anything out of the ordinary with the old lines or the ports on the back of the compressor.

I got the system recharged today. I let it sit under vacuum for about 45 minutes the first time and a little over an hour after the second vacuum. The needle on the gauge never moved. I'm sure it was not needed but I let it vacuum and rest quite a bit longer than I normally do, mostly because I was doing other stuff at the same time.

After I got it charged and with the AC still on and the car running, I got under the car and could not see any oil around where the manifold lines hook to the compressor. Before the repair, you could see what looked like a tiny bubble form on the suction port. Hopefully this means that the manifold assembly is sealing correctly this time with the new lines.

I guess time will tell to see if the leak is fixed.