Do new AC compressors come with oil? We answer

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So, do new ac compressors come with oil?

The short answer is: YES! A huge number of AC compressors brands nowadays come pre-loaded with the exact amount of oil and you don’t have to worry about adding the fluid before installation.

In a nutshell, many of the models will be ready for fixing right out of the box.

Of course, the function of AC compressor oil is to make sure that all the internal moving parts are properly lubricated and cooled.

In addition, the oil film protects the seals in the lines and connections further reducing the quantity of refrigerant that leaks out.

Here is the thing: there is always a chance that your AC compressor won’t come pre-filled with oil from the factory.

Besides, some manufacturers recommend that you drain the “shipping oil” and refill with “proper” oil ahead of installation – the other purpose of the added oil is to protect the compressor during its stay on the dealers’ shelves and in the course of transport.

What’s more, it is imperative that you add oil for some applications..

A good example is where the quantity of oil in the new compressor differs from your vehicle specifications.

Now, in such situations, there are a few things you need to know.

You’ll learn about these and more tips in our long answer..

Do new AC compressors come with oil? Long answer

As I have mentioned before, AC compressor will largely come pre-oiled these days.

Our interest in this section is on the exceptions- when it’s not pre-loaded or comes with “protective” oil.

Here is the best approach:

First, check what the compressor instructions say about oil- this is the most important thing in deciding the route to take.

You then proceed as follows:

Just in case it didn’t come with oil, you need to add the number of ounces specified in the stickers or accompanying documentation.

The other super important thing is to use the specific oil recommended by the manufacturer for the unit to avoid problems down the road.

That’s because different types of oils have dissimilar properties (think of viscosity and the like) and mixing them could trigger endless issues including compressor seizure and permanent damage because they might not mix well with refrigerant.

Now, the easiest way to determine the correct AC compressor oil type to use for your compressor is by reading the identification label- it’s typically attached to the side or rear of the compressor.

I must add that the label is very handy since it also displays the amount of compressor oil inside your new compressor (for pre-oiled brands).

This is crucial because it will give you a clear idea of the right quantity to load into the part.

Note that this information is printed in the literature inside the package in some cases.

What to if the suitable oil amount is unclear

You see, it’s not guaranteed that you’ll get all the guidelines about the appropriate amount and type of oil.

Luckily, there is a nice workaround if you’re in this dilemma: just drain the old AC compressor and measure the amount of oil that comes out (You’ll obviously require an ideal measuring device).

All you’ll need to do is add the same volume of the lubricant when refilling instead of relying on guesswork.

Tip: You can as well check your car’s manufacturer data to be sure of the correct oil quantity to add if your AC system specifications differed.


What else must you keep in mind?

·         The new compressor must be drained the right way

Where you’re required to drain the pre-added oil from the new compressor, you must follow the steps indicated in your compressor’s installation guide.

Here is a general procedure to follow:

Draining procedure

Remove the compressor’s drain plug and drain the maximum amount of oil from the unit into a container.

Be sure to tilt it back and forth severally to have all the oil flow to the drain hole.

Tip: Don’t forget to measure and note the quantity of oil you’ve emptied from the new compressor if necessary.

·         Follow the correct procedure when adding oil

Though it’s not really difficult, you need to be careful when adding oil.

As a guide:

  1. Add the specified quantity of fresh oil (or an amount to what you drained) into the emptied compressor – you usually add via the hose input on the high side on your compressor unless otherwise indicated.
  2. Reinstall the oil drain plug.
  3. Recharge it according to your AC system’s requirements.

A word on flushing the system

It’s a good practice to flush the entire AC system- you can flush it using a flushing agent combined with compressed air- if you doubt the amount of oil in there and want to fill it up.

If you take this option, the rule of thumb is to load half your system’s total oil capacity into the AC compressor and the remaining half in the receiver dryer or accumulator.

Also keep in mind that there’ll be instances where other A/C components require replacing during the process.

In such a case, you must again refill the right amount of oil in each A/C component.

The following table can point you in the right direction when it comes to replacing oil in the separate components:

AC component Ounces of oil to add (Typical)
Condensor 1 ounce.
Evaporator 2 ounces.
Accumulator 2 ounces.
Filter drier 1 ounce.

Please check your system’s specifications on the documentation or the manufacturer’s website for clarification (your goal is to have the factory-recommended oil amount in the parts at all times).

Do new AC compressors come with oil? Take-aways

AC compressors come pre-filled with enough oil to run the entire AC system in many cases.

However, there are instances where you’re required to empty the “shipping” oil and load the component with the right amount of the correct type of AC compressor oil prior to installing it.

In instances where other parts require replacement, you must load the correct oil amounts for each component for proper functioning (use the table we have included above as a guide).


Too much oil in AC system symptoms and troubleshooting tips


1 thought on “Do new AC compressors come with oil? We answer”

  1. Do new replacement accumulator/dryers come pre-filled with oil, if so, what type? My system uses mineral oil, 1986 Chevy Astro and if they come pre-filled with PAG I’m screwed. Can it be drained and flushed?


    Mike W.


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