Maintenance Tips

How Much PAG Oil To Add To AC System


For a car, the air conditioning system requires a specific amount of oil to operate, just as the engine does.
You need to have a good understanding of how much PAG oil is applied to the AC system to save yourself from unexpected failure.

Which AC Components Require an Oil Refill?

The compressor is the part of the AC unit, It needs enough oil to run smoothly.

Typically, there is no need to add oil to the current AC system of your car unless you have modified the compressor or a leak happens, causing the system to drip oil.

For lubrication, a compressor needs an appropriate amount of oil.
It has several cylinders to compress refrigerant gases, and it generates heat and friction.
Oil regulates the heat in the system and reduces friction by making the parts slipperier.

If there are any leaks in the system before adding the oil, they should be fixed.
Otherwise, the system will soon need more oil, and some parts can malfunction.

What Is PAG Oil?

PAG oil, or Polyalkylene Glycol, is made specifically for automotive AC compressors.

The fully synthetic hygroscopic oil is a compressor lubricator that uses R-134a refrigerant for the AC systems.

In addition to understanding how much PAG oil you need to apply to the AC system, you must also use the right viscosity oil.

PAG is a synthetic oil for AC compressors.

Every form of PAG oil has such a number as PAG150 or PAG VC-46.

This number refers to the PAG viscosity, similar to a number like 10W30 indicates the viscosity of regular engine oil.

To find out the right PAG oil viscosity for the AC’s compressor you need to look into the owner’s manual.

How much PAG oil should be added to the AC system?

The compressor of the AC system is likely to have specifications regarding the amount of oil to be added.
If you are adding too much oil, you should definitely check the owner’s manual.

The AC system requires a Usually of 4 ounces (120 ml) of oil in most modern automobiles.

So it is a good idea to test the manual to be sure of the exact amount and to prevent over- or under-filling of the system.

Low oil levels can cause compression failure and overfill often hurts the efficiency of the cooling cycle.

Don’t overfill the system.

Here is the amount of PAG oil needed for its smooth operation by different AC components:

  • Compressor = 1.4 ounces
  • Evaporator = 1.5 ounces
  • Condenser = 1 ounces
  • Accumulator = 1 ounces
  • Hoses = 1 ounces

It’s suggested to flush the whole system before adding oil or refrigerant.

When you are replacing a part, such as a compressor or an accumulator, you should always add the oil that has been lost during the replacement.

If replacing a component, like a compressor or an accumulator,
You should always add oil lost during the restoration process.

The total amount of oil added will never exceed the oil capacity of the system.

So, When calculating how much PAG oil to add to the AC system,
Always remember to keep the total amount under 4 ounces or
Whatever the capacity of your car’s AC system is.

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Published by
The Engineer

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