How to Add Refrigeration Oil to the Air Conditioning Compressor?

[OMason]

There are mainly three methods for adding refrigeration oil to the compressor. The following are the methods for adding refrigeration oil to the compressor: 1. Direct Addition: Add directly from the compressor. First, perform an oil return operation, which means running the compressor at idle speed with the control system set to the coldest and highest fan speed for 20-30 minutes to allow the oil to return to the compressor. Then, turn off the engine, release the refrigerant, remove the compressor from the vehicle, drain the old oil, and directly add or replenish new oil. 2. High-Pressure Side Addition: Add from the high-pressure side. Evacuate to 98 kPa, close the high-pressure side manual valve, and close the compressor service valve. Remove the high-pressure side hose from the pressure gauge head and insert it into the refrigeration oil. Open the service valve, and the refrigeration oil will be drawn into the system. Close the service valve immediately when the oil is almost fully drawn. 3. Low-Pressure Side Addition: No service valve is required. After evacuating to 98 kPa, close the low-pressure side manual valve and continue evacuating with the vacuum pump while keeping the high-pressure side manual valve open. Remove the low-pressure side hose from the pressure gauge head and insert it into the refrigeration oil to draw the oil. After drawing, reattach the hose to its original position, open the low-pressure side manual valve, and continue evacuating. Once evacuation is complete, proceed with the refrigerant charging operation.

[VonJoshua]

Adding refrigerant compressor oil is something I've done several times. The first step is to make sure the system is powered off—safety first. Then recover all the old refrigerant properly using a dedicated machine, otherwise it's both environmentally hazardous and dangerous. Choosing the right type of compressor oil is crucial—PAG oil is common, but always check your car's manual. When adding the oil, locate the compressor's oil fill port and slowly inject it using a syringe or oil gun. The oil quantity must be precise—too much can cause foaming and affect cooling, while too little may lead to dry friction and compressor damage. Every time I finish, I check the dipstick or sight glass to ensure the level is just right. Finally, don't forget to evacuate the system, recharge it with new refrigerant, and test-run it. The whole process takes at least half an hour—if you lack the proper tools, don't force it. Once, I rushed and didn't wait for the system to fully shut down, ending up with oil spraying all over me. Later, I wisely took it to a repair shop. This job truly requires patience and expertise—otherwise, a broken AC will cost way more to fix.

[SanMarley]

My car's AC wasn't cooling last time, so I tried adding refrigerant oil myself. First, I went to the auto parts store to buy a suitable bottle of oil, remembering the type like PAG or ESTER depending on the vehicle model. After returning home, I turned off the engine and used a recovery pump to drain the old refrigerant to prevent leaks. Then, I opened the small cap on the compressor and carefully injected the oil with a syringe, making sure to do it steadily without rushing. The amount needs to be controlled, usually around 10% of the compressor's capacity, as overfilling can cause foaming and poor performance. After adding the oil, I tightened the cap and refilled the refrigerant before testing the AC. The whole process was quite laborious, and the tools cost a bit, but I saved on labor fees. The result? The AC cooled down, but a month later, I noticed a tiny leak, probably due to improper sealing. So, it's better for non-professionals not to tamper with it and just call a technician for a more reliable and worry-free fix to avoid unexpected issues.

[Sylvia]

Let me briefly explain the basic method of adding refrigerant oil. First, turn off the engine and wait for the system to cool down - safety is paramount. After completely discharging the old refrigerant, use the proper tools. Check the compressor oil port and inject an appropriate amount of new oil, with PAG oil being the standard choice - never mix types. The oil quantity must be precisely controlled to avoid overfilling or underfilling, as insufficient lubrication can damage the compressor. After adding, test the system operation to confirm normal functioning. I must remind everyone that improper operation can easily cause leaks or reduced efficiency, so it's safer to have a professional technician handle this whenever possible.