Does a new AC compressor come with oil in it already?

Typically, automotive A/C compressors arrive pre-filled with the proper oil, while home HVAC compressors are often shipped dry and require you to add the correct oil charge during installation.

What this means in practice

Oil is essential for lubrication and sealing inside any air-conditioning compressor. The way the oil is handled before the unit leaves the factory varies by system type, manufacturer, and whether you’re buying a part for a car or a home HVAC unit. Here’s how it breaks down by system.

Automotive air conditioning compressors

Car A/C replacements are commonly shipped in one of two ways: either with oil already inside the compressor, or dry and needing the correct oil added during installation. The right oil type and amount depend on the refrigerant used and the specific compressor model.

Here is a quick breakdown of what to expect with automotive units.

• Many OEM and remanufactured automotive compressors are pre-filled with the correct oil inside the unit


• Some aftermarket/new compressors are shipped dry and require you to add the proper PAG oil during installation


• Oil type depends on refrigerant: PAG oil for R-134a systems; newer R-1234yf systems may require POE oil


• The exact oil charge varies by model; always verify the specification from the supplier and follow the installation manual

Getting the oil right is critical: too little or the wrong type can cause lubrication gaps, overheating, and damage to seals and the compressor itself.

Home HVAC compressors

In residential central AC and many ducted/mini-split systems, the compressor is part of a sealed refrigeration circuit. Replacement compressors are often shipped dry, and the correct oil volume and type must be added as part of the job, either by transferring oil from the old compressor or by charging the system with the appropriate oil during service.

Here are key considerations for HVAC replacement units.

• Many HVAC replacement compressors are shipped without oil and require adding the correct oil charge for POE oil used with R-410A or other refrigerants


• Oil type depends on the refrigerant: POE oil is common for R-410A; older refrigerants or different systems may require other lubricants


• If you replace only the compressor, it may be necessary to transfer oil from the existing system or top up the charge under professional guidance


• Some kits include the oil charge; always confirm the amount and type with the seller or installer

Because incorrect oil charge can reduce efficiency or cause compressor failure, many professionals handle the replacement to ensure the oil and refrigerant charges are correct.

Practical steps before installation

To minimize risk, check the product documentation and packaging for the oil status, confirm the oil type and amount required, and be prepared to source the correct oil if needed. If you’re not sure, hire a licensed technician to perform the replacement and oil charge transfer.

Summary

In short, a new compressor’s oil status is not universal. Automotive compressors are often pre-lubed, but home HVAC compressors are typically shipped without oil. Always verify the supplier’s documentation and consult a professional to ensure you use the correct oil type and quantity for your refrigerant and model.

Do I need to put oil in my new AC compressor?

Turn it upside down on the collection device for at least 8 to 10. Hours. Once you drain the oil out of the compressor.

Do four seasons AC compressors come with oil?

New compressors include the required R12/R134A/1234yf O-rings/sealing washers to install the compressor, direct fit connectors for ease of installation and to help eliminate splicing, and are pre-charged with 3 ounces of PAG oil for R134a or R1234yf applications.

How much oil does a new AC compressor come with?

Does the new compressor contain oil? 300 cc (10 oz) Many compressors builders list the oil amount on the label, but not all. Some may show it on the under hood label.

What does an AC compressor kit come with?

An AC compressor kit typically includes a new compressor with a clutch, a drier/accumulator, an expansion valve or orifice tube, compressor oil, and all necessary O-ring seals and gaskets. Some kits may also include other components like a condenser, but these are the most common parts included to ensure a complete and successful AC repair. 
Core components in a kit

• Compressor and clutch: The central pump of the AC system, powered by the engine's drive belt. 
• Drier/Accumulator: A filter that removes moisture and debris from the refrigerant. 
• Expansion valve or orifice tube: Controls the pressure and flow of the refrigerant into the evaporator. 
• Compressor oil: Lubricates the compressor and other moving parts; some kits may require draining and replacing the shipping oil. 
• O-rings and gaskets: Sealing components for all connections in the system. 

This video shows what is inside an AC compressor kit: 57sBrilliant Auto CareYouTube · Jul 1, 2024
Additional components sometimes included

• Condenser: A component located near the radiator that cools the hot refrigerant. 
• Hoses: Some comprehensive kits might include replacement hoses. 
• System treatment: Some kits include additional products to help clean and treat the system.