Step-by-Step Guide: How to Check and Refill Oil in Your AC Compressor


Checking the oil level in an air conditioning compressor is a vital part of maintenance to ensure the long-term health and performance of your AC system. This guide will provide step-by-step instructions on how to accurately check the oil in your AC compressor.


The oil in an AC compressor lubricates the compressor unit, which helps to prevent the buildup of friction and heat that can cause damage over time. It’s essential to maintain the appropriate oil level to keep your AC compressor running smoothly. With the right tools and a little bit of know-how, you can learn to check the oil in your AC compressor yourself.

Safety Measures and Equipment

Before we delve into the process, let’s review the necessary safety measures and equipment needed for this task:

Safety Glasses: Eye protection is crucial when dealing with potentially hazardous materials like compressor oil.

Gloves: Compressor oil can irritate the skin, so it’s important to wear protective gloves.

Oil extractor pump: An oil extractor pump is necessary to remove oil from the compressor.

Rechargeable oil: You’ll need the correct type of oil to recharge your AC compressor.

AC manifold gauge set: This set allows you to monitor the pressure levels of your AC system.


Step-by-Step Guide

Prepare your tools and equipment: Gather all the necessary tools and equipment listed above. Preparation is the key to any task, and it’s especially important when dealing with complex machinery like an AC compressor.

Safety first: Ensure you’re wearing your safety glasses and gloves before you start working. Your safety should always be your top priority.

Identify the compressor: The compressor is typically located in the outdoor unit of your AC system. It’s a large, cylinder-like object that’s easily identifiable.

Access the compressor: Turn off the AC unit and disconnect it from the power source for safety reasons. Then, carefully remove the outer casing of the AC unit to expose the compressor. This might require unscrewing some bolts or screws.

You May Also Like:  How to Reset a GE Front Loading Washer: A Step-by-Step Guide

Locate the oil port: Once you have located the compressor, identify the oil port. This is typically marked with an oil or fluid symbol, or it may be mentioned in your AC unit’s manual.

Connect the oil extractor pump: Now, you need to connect the oil extractor pump to the oil port. This can usually be done by screwing it onto the port.

Extract the oil: Once the pump is securely connected, start the pump to begin extracting the oil from the compressor. Be sure to have a container ready to collect the oil. This process can take a few minutes, depending on the amount of oil in the compressor.

Measure the oil level: After you have extracted the oil, use a measuring cup to find out how much oil was in the compressor. Compare this to the recommended oil level stated in your AC unit’s manual.

Recharge the compressor with oil: If the oil level is lower than the recommended amount, you’ll need to recharge the compressor with oil. Use the oil that’s recommended in your AC unit’s manual. Pour the oil slowly and carefully into the oil port, being sure not to overfill the compressor.

Recheck the oil level: After you’ve added oil, you should recheck the oil level to ensure it’s at the correct amount. If it’s too high, you’ll need to extract some oil. If it’s too low, add a bit more oil.

Close the oil port and reassemble the AC unit: Once the oil level is correct, remove the oil extractor pump and securely close the oil port. Then, reassemble the AC unit, reconnect it to the power source, and turn it back on.


This process may seem daunting, especially if you’re not familiar with AC systems. However, it’s a critical part of maintaining your AC unit and ensuring it operates effectively. If you’re ever unsure about any step in this process, it’s always best to consult with a professional.

You May Also Like:  Tips and Tricks to Unlock Mitsubishi Thermostat

It’s essential to keep in mind that different AC systems may have different requirements, so always refer to your specific unit’s manual before starting any maintenance work. The type of oil, the recommended oil level, and even the location of the oil port can vary between different models.

Additionally, if your compressor seems to be losing oil frequently or if it’s operating poorly despite having the correct oil level, there could be other underlying issues. In such cases, it’s best to contact a professional who can diagnose and fix the problem.

In conclusion, checking the oil in your AC compressor is an important skill to learn. It can help you extend the lifespan of your AC unit and ensure it’s always operating at peak performance. With practice and patience, you’ll soon be able to perform this maintenance task with ease.