Refrigerant and A/C compressor oil filling quantities (2024)

FAQs

How much PAG oil to add when recharging AC? ›

The AC system in most modern vehicles needs a total of 4 ounces (120 ml) of oil. So, checking the manual is a good idea to be sure of the exact amount and to avoid over- or under-filling the system. A low level of oil may cause compression failure, and overfilling will also hurt cooling performance.

There is a significant range in how much oil air compressors require, with no clear standard across manufacturers. VMAC air compressors hold approximately 1-2 gallons (4-9 liters) of compressor oil, depending on the VMAC system, but other systems may contain more or less oil.

If you hear a strange humming noise when switching on your car's A/C system, you may lack compressor oil. Remember, compressor oil's main function is lubrication. When there isn't enough oil to lubricate the parts in your car's A/C compressor, they may grind together, causing a humming noise.

For a full system evacuate and recharge (R134a, '94 Jag XJ6), how much oil should go into the system with the refrigerant? According to my Haynes techbook, you need 4 to 5 oz.

In most compressors, the oil level in the sight glass should be between ¼ and ½ sight glass. Too little oil in the compressor results in an obvious oil trip. Too much oil in the compressor can also cause oil trips.

Excess oil may accumulate in the evaporator and then return to the compressor in a slug. This could overfill the crankcase and possibly damage the compressor. Excessive amounts of oil in an evaporator decrease the capacity of a system.

If your compressor is going into a system that has previously been installed, it's important to get as much of the original oil charge out of the system as possible to protect against an oil overcharge. It's typically ok for an extra ounce or two of oil to remain in the system, provided it is contaminant free.

Vacuuming only removes gases, not liquids. Oil doesn't change state to gas, it stays liquid and therefore it will not get sucked out.

However, filling your compressors oil sump to the top can cause significant internal damage to your unit. When excess amounts of oil become aerosolized by the compressor's discharge, it can cause damages not only to your compressor, but to any pneumatic tools and accessories that are hooked up to your compressor.

Non-Detergent – if it's compressor oil, it should automatically be ND. Viscosity Grade of 20 or 30 SAE – 30 in normal environments, 20 in cold temperatures.

How many ounces of oil do you put in a new AC compressor? ›

The goal is to maintain the new OEM amount of oil. 3 ounces In this example the removed compressor contains 3 ounces so the new compressor should have 3 ounces as well. This way we maintain the original 10 ounce oil charge consistent with the new system. Drain and measure the oil amount contained in the old compressor.

As a result, if an A/C compressor doesn't have enough oil, it may not be able to cool air or may experience other issues. The easiest way to avoid this problem is to be aware of the indications of low oil in the A/C compressor and to take action as soon as you see them.

If you recharged your vehicle's air conditioning system with freon and it still isn't working, or if you have a newly installed AC compressor, you may need to put oil in it. Take your vehicle to a certified mechanic if you don't have a reclaimer machine, which you need to capture the freon from the AC system.

With R-134a, there are primarily three different viscosities of PAG oil being used: PAG 46, which is the most popular viscosity oil; PAG 100, which is also common; and PAG 150, which is not often used, but it is still required for a certain compressor used in some GM vehicles from the '90s to the early 2000s.

Share via. Air compressors require constant oil lubrication to prevent friction on the pistons or screws and other moving parts. To make sure your air compressor is running efficiently, it is important to check your oil level regularly and to know how much oil your compressor needs.