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How To Add Oil on AC System Using Simply an Oil Injector

Add Oil on AC System Using Simply an Oil Injector

Your car’s air conditioning (AC) system is what brings you to a more comfortable and cool feeling when you are driving under the heat of the sun. When the AC stops working, you will probably go berserk! But there are several ways to avoid this thing to happen to your air conditioning system.

The machine that runs your AC is its mighty compressor. When this thing overheats, it will go nuts and give you lots of headaches! Most compressor malfunction due to lack of oil to lubricate the system.

Once the oil is dehydrated, the compressor is bound to fail, and worst, it could create severe damage to the compressor. We will teach you how to add oil to your AC system using simply an oil injector, only here. Read on, car lovers!

How do you know your compressor needs additional oil?

Most cars will not engage the clutch compressor of the AC system when it senses that there is an inadequate amount of oil in the compressor. The system will trigger a default reaction when the clutch compressor senses that the oil content is below the required oil level. At this instance, the clutch compressor of your AC system will be rendered inoperable.

add oil for a car

Add oil for a car

To avoid this to happen, you must add oil to the compressor whenever the need arises. You may consult your AC manual for this. Here are the simplest things to do to know if the AC compressor unit needs additional oil:

    • If your car is running, shut off the engine first. This will also shut off the air conditioning system.

    • Let the oil on the compressor settles for a while. And let the compressor cools off.

    • After about such time that you figure out that all of the oil in the system has settled down, look for the sight glass of the compressor.

    • After finding the compressor’s sight glass, make sure it is clear enough to look at. If not, wipe the glass with a clean cloth until it is clear enough to see its content.

    • The sight glass will tell you how much oil is remaining in the compressor. The ideal oil content is halfway through the sight glass. But it is still safe at the 1/3 level. Below this level, the compressor will begin to dehydrate of oil, especially if there is a leak in the system.

    • Experts agreed that adding oil at the 3/4 level of the sight glass is an ideal level. Oil dissipates while it circulates around the system, that is why it is safe to add oil up to this level.

The oil lubricates the moving parts of the compressor and the refrigerant that circulates around the system. It goes with the refrigerant which also minimizes friction while the refrigerant travels through the tubes, rendering efficient circulation.

How would you know the type of compressor oil to use?

Brand new cars straight from the factory have no problem finding the compatible oil for the compressor of their AC system. This is surely written in the manual or printed in the car’s compressor. Older cars with their owner’s manual long gone or no trace of written instructions on the compressor will certainly have a problem.

The same with cars that have been fitted with another brand of AC system as a replacement. However, almost all AC systems have the sticker pasted on its compressor identifying such oil type to use. While a car with an AC system that had not been replaced since its purchase has an information sticker about the system under the hood of the car near the compressor.

For cars that have no traces or any sign of its compressor oil type, the best thing is to call or email the manufacturer of their AC system. Or they may contact their car dealership about the right compressor oil to use.

But this should not be a cause for you to worry. There are various types of compressor oil that are compatible with most refrigerant types (most modern cars use R134a) available on Amazon. You can check out our expert tips about these products later on this article.

What you will need

    • Compressor oil (compatible with your AC system)

    • AC oil injector (syringe type)

    • UV Dye (optional)

    • Flashlight

    • Safety gloves

Adding oil to an AC compressor

the man working under the car hood

The man working under the car hood

    1. With the car’s engine off, open up the hood of your car. Use your flashlight to illuminate dark spots inside the car’s engine compartment. And don’t forget to use safety gloves before you do this activity.

    2. Look for the oil valve on the low-pressure side of the compressor (located after the compressor’s low-pressure side check valve).

    3. Take the cap off the valve of the low-pressure side.

    4. Take the syringe type oil injector and fill its plunger with oil up to a quarter of its full capacity (typical syringe type oil injector has 1/2 oz capacity).

    5. Clip the injector valve with the compressor’s low-pressure side valve.

    6. Push in the content of the oil injector syringe slowly. Stopping intermittently and then let gravity do its thing.

    7. Reload another batch of oil into the syringe oil injector and repeat no. 5, until you attain the right level of oil by peeking at the sight glass.

    8. After attaining the right level of oil, release the valve of the injector from the compressor oil valve and put back its cap.

You can add industrial UV dye into the oil if you suspect there is a leak in the system. This dye is not corrosive, will not clog the system, and dissolves with the compressor oil. You can use UV light or blue light to spot the leak.

Expert mechanics use the FJC 4910 Universal A/C Fluorescent Leak Detection Dye to detect a leak. This product is available on Amazon, typically safe for hybrid cars, and can be used for R12 or R134a type of refrigerants.

Pro Tips from the experts

1. These oil injector brands are recommended by most expert mechanics across the United States, you can try either of these and they are readily available from Amazon:

2. For your quick reference, these are some of the most used compressor oils by car enthusiasts on their AC system, according to experts. But first, check them out if any of these types fit your system. All are readily available on Amazon with free shipping.


Did you enjoy this tutorial? We hope you do. You can certainly predict one of the most annoying situations you will have into; A shut-off AC system while you are driving in the middle of a hot summer day. But you have now the knowledge to foretell if this would happen to you. You will certainly act accordingly to avoid this embarrassing situation.

Now you know how to add oil on your AC system using only an oil injector, you can always seek the help of your most trusted mechanic if you notice there is something unusual about your AC system.

Please share this article if you enjoy it and send us your comments.

About the author

Carolina - Care My Cars

Car, from a long time ago is the main transport vehicle for people which help to move faster and protect users from the unstable of weather such as sunlight, heat, or rainy. So that, the demand of car and the search for the best and a suitable car in the market are higher than ever and you also are one of the people who is looking for the answers from the market. Welcome to caremycars.com and I hope that my articles can help you to solve the problems that you are in with the most effective way. If you think my website give values, you can donate me by the ways. Donate: - Bitcoin (BTC): 1Eoz8vhfAjD4cCrq2jec3V38mmaHehedXU - Etherium (ETH): 0xd10809ae634117bf6c52Af884a8bc8B84D436e3b - BicoinCash (BCH): qqp4yjqx2g57exes0stsnkgk5e9uyu5clvrjj4ew44 Thank for all


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