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

FAQs

How much oil to put in an 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.

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.

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.

Each make and model of air conditioner needs a slightly different amount of AC refrigerant. According to PG&E, most central air conditioning systems use two to four pounds of refrigerant per ton of cooling capacity. A three-ton air conditioner would typically have six to 12 pounds of refrigerant for a proper charge.

It may be found on the base of the pump for reciprocating type compressors or on the sump tank in a rotary screw compressor. In the middle of the sight glass, you will see a dot. Ideally, you want the oil level to be in the center of the dot. If the oil level is below the dot, your unit needs more 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.

In most cases the only time it is necessary to add an oil charge is if there is major damage or if a component is replaced in the system. If the system has become low due to a small leak, it is likely that most of the refrigerant oil is still in the system despite the fact that refrigerant has escaped.

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.

Putting too much oil in the compressor will not shorten its life. But if this oil gets ejected through the compressed air line, you will notice a drop in the compressor's air quality. In short, putting too much oil in the compressor will cause the compressor to leak oil or compressor oil to get into the compressed air.

In refrigeration compressors, oil and refrigerant mix continuously. Refrigeration oils are soluble in liquid refrigerant and at normal room temperatures they will mix completely.

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

Under normal circ*mstances, you shouldn't need to refill or change the oil in your AC system's compressor. Most new compressors already come with oil. And because compressors are sealed, neither oil nor refrigerant should escape. But compressors can leak.

This is a very difficult question to answer. It depends on the size (capacity), equipment selection, refrigerant type, and length of refrigerant piping. Typical residential systems hold between 5 and 20 pounds of refrigerant. On average it's about 3 pounds per ton (12,000 BTU) of air conditioning.

No complicated math required, you simply add together the gas in the pipe, the compressor/condenser section, and the evaporator = total charge.

Most homeowners will pay in the range of $200 to $400 for a refill, depending on the type and size of their HVAC unit. If you own a larger r22 unit, you may have to spend $600 or more. To break this down for you, a 25lbs unit of r410A costs anything between $100 and $175.

Putting too much oil in the compressor will not shorten its life. But if this oil gets ejected through the compressed air line, you will notice a drop in the compressor's air quality. In short, putting too much oil in the compressor will cause the compressor to leak oil or compressor oil to get into the compressed air.

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.

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.

You add PAG oil to the high side of the AC system. The high side is typically the yellow hose.