The high-pressure AC hose on my 2003 Subaru WRX has developed a leak, and I need to replace it. I also plan to replace the accumulator/drier at the same time. It appears almost no oil was lost from the leak. I do not have detailed manuals for the car, so does anyone know the proper amount of oil to add when replacing these components?

edit: There is currently a negligible amount of refrigerant in the system because it leaked out. I will be borrowing a vacuum system to evacuate the system after replacing parts. My research indicates that repair shops cannot remove the oil with their vacuum machines, so they usually add a percentage of the total oil capacity based on what components they are replacing. What is the AC compressor oil capacity for my car, and what percentage is replaced when replacing the accumulator/drier?

2 Answers 2


Checking the pg. 28 of service manual suggests that you don't need to add any oil for replacing the dryer itself - just the 1ml for the replacing the hose:

Replacement parts Amount of oil replenishment
Evaporator 114 ml (3.9 US fl oz, 4.0 Imp fl oz)
Condenser 7 ml (0.24 US fl oz, 0.25 Imp fl oz)
Hose 1 ml (0.03 US fl oz, 0.04 Imp fl oz)

PS: While the manual linked to above is for an '04 car the figures are exactly the same for an '03 model like the OP's (I've checked my off-line copy of the 02-03 Service Manual)

  • Now this is a real answer. On point and direct. Jun 4, 2021 at 11:11
  • @Pᴀᴜʟsᴛᴇʀ2 OP asked for the compressor capacity and its not in the answer... However, it could be in the manual but it makes your comment incorrect.
    – Solar Mike
    Jun 4, 2021 at 13:38
  • 2
    @SolarMike The "main" question the OP asked was "does anyone know the proper amount of oil to add when replacing these components?", which is what I've answered here. The manual doesn't actually specify the compressor capacity, stating "When replacing the compressor, the new compressor will already have the specified amount of oil in it." Jun 4, 2021 at 14:13

Both places I use have the machine to remove refrigerant and oil, test for leaks then refill with correct amounts of oil and refrigerant.

I would not take a risk but get it done professionally, the previous owner of my car wrecked the compressor...

  • 2
    This does not answer my question. For me the risk is worth it because my options are to attempt the fix myself, or go without.
    – Orienteer
    Jun 3, 2021 at 17:54
  • 1
    @Orienteer good, your choice - just don’t under or over fill the tolerance is fine. Not like plus or minus a pint in the sump...
    – Solar Mike
    Jun 3, 2021 at 18:00
  • 1
    @SolarMike How do they remove the oil? The usual machines I'm familiar with are basically just vacuum pumps that do remove some of the oil that rides along with the refrigerant but apart from total disassembly I can't imagine how you would even get most of it out.
    – jwh20
    Jun 3, 2021 at 18:50
  • @jwh20 - I was wondering that as well. Seems there's a sump called a compressor which would collect some of the oil. I didn't think the oil stayed in suspension within the refrigerant. Jun 3, 2021 at 19:43
  • 1
    @Pᴀᴜʟsᴛᴇʀ2 Maybe some words got lost in "there's a sump called a compressor" but the compressor is the device that compresses the refrigerant gas to raise its temperature before it cools down to ambient temperature to dump the heat outside the car and then expands to cool below ambient. The oil sump is just a sump. Undissolved oil in the compressor will destroy the compressor. Undissolved oil blocking the tubes in either of the heat exchangers means there is no refrigerant circulation and no cooling.
    – alephzero
    Jun 4, 2021 at 2:48

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .