I installed a new AC compressor on the Solstice of Sorrow the other day, but haven't turned it on yet. I'm planning on recharging the system this evening.

Now, before I do this: am I supposed to oil the compressor or anything? The new unit (AC Delco) has some oil in it, but I'm not sure if that's supposed to be adequate, or if it's the correct oil. I hope it's the correct oil as I don't see a good way to drain it.

It's this one:


AC Delco 15-21505

It would also be nice if it were possible to check the system for leaks before refilling it with expensive refrigerant. :/

  • I'm by far not an expert on this, but I thought you had to draw a vacuum on the system first. Then you leave the system under vacuum and verify the pressure reading doesn't change over a period of time. Then fill the system.
    – rpmerf
    Jun 14, 2017 at 20:06
  • @rpmerf That makes perfect sense. Now I just have to figure out how to connect my Air Lift to the AC system. :)
    – 3Dave
    Jun 14, 2017 at 20:38
  • 1
    You can get a cheap venturi style vacuum pump from HF. They work really well for drawing a vacuum. You may also need the manifold gauge set if you're going to do this yourself. Helps in the long run. Jun 14, 2017 at 20:48
  • @Pᴀᴜʟsᴛᴇʀ2 I have a vacuum pump, just need to figure out how to attach it to the AC system (fittings, etc.). Thanks for the links!
    – 3Dave
    Jun 14, 2017 at 20:50
  • A manifold gauge set would most likely help you getting things attached. Would also tell you if the SOS A/C system is holding vacuum. Jun 14, 2017 at 20:51

1 Answer 1


Unless otherwise indicated with information included with the new compressor, add 4-6 ounces of the recommended oil into the suction side port of the compressor, rotate the compressor by hand in the direction it normally turns about 10 revolutions, install, evacuate and charge system.

Some compressors come with oil charge some do not, it is usually indicated in the paperwork included with the new pump.

Evacuating the system with a vacuum pump will indicate any leaks, if you are not experienced in AC service consult with someone who is before doing this type of work, as it can be rocket science to the inexperienced.

  • Thanks. The car service manual says the compressor comes with 2.5oz of oil in it, but that the system has to be balanced. That is, if the old compressor had more than 2.5oz in it, add the different to the new unit. Unfortunately, the old one was bone dry so I have no way to tell if it had more. I've recharged these before, but not with a new compressor. It's the same OEM Delco model as the old one.
    – 3Dave
    Jun 19, 2017 at 13:17
  • @DavidLively if the compressor is bone dry then the rest of the system is too, bone dry means no oil circulating which means the entire system is dry (leaked out with the freon over time), add the full amount of oil for the system less what is in the new compressor.
    – Moab
    Jun 20, 2017 at 23:50
  • @Moab thanks. It didn't leak - got discharged during an engine replacement. The compressor old compressor is dry because it was stored upside down without any sort of block on the ports. I've seen some refrigerant that says it includes oil in the mix. ??
    – 3Dave
    Jun 21, 2017 at 19:11
  • I don't like Freon with oil (called oil charge), manually add proper oil to the compressor as suggested.
    – Moab
    Jun 21, 2017 at 22:53

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