AMSOIL Compressor Oils

It was true when I made the first draft of this page and it is still true today. AMSOIL’s performance gains in your compressor operation no matter the size vastly improves protection and energy expenses.


Thank you for looking over AMSOIL Compressor Oils. As a dealer for AMSOIL, the compressor oil sales have been our #1 best selling product when it comes to large container sizes.  Coming from our customers, there is nothing average or run of the mill when it comes to the AMSOIL compressor oils.  AMSOIL’s quality will astonish you. The rule of thumb is the OEM product is a profit driver and for that reason cannot be made to the best performance standards of a private brand which designs and blends their own products. AMSOIL offers the most advanced state of the art quality for a price which many cannot beat. I’ve had several large industrial firms such as General Dynamics test the AMSOIL product over others and conclude ours outperforms by a wide margin!

If you are buying Compressor Oils for your business call us (800-579-0580) to get established as a commercial account for the best price.

Or you can set up your own Commercial Account so you get AMSOIL Products factory direct at the lowest price.

AMSOIL synthetic compressor oils increase the productivity and profitability of your operations. By providing superior overall lubricating performance, you can expect longer lasting compressors, fewer unscheduled maintenance requirements, less oil consumption and improved operating efficiency. In addition, AMSOIL compressor lubricants last several times longer than conventional lubricants resulting in lower maintenance and waste oil disposal costs. Through better lubrication, AMSOIL improves your bottom line.

Synthetic PC Series Compressor Oils

Our best selling Compressor oils. Promotes reduced energy consumption. Low frictional properties (ISO 32 through 150, SAE 10W through 50)
The correct manufacturer-recommended viscosity grade of AMSOIL PC Series compressor oil is recommended for use in rotary screw, rotary vane, reciprocating and other compressor applications. Compatible with PAO-, ester- and petroleum-based compressor oils. They are not compatible with glycol- or silicone-based compressor oils. Consult Us Here for further information.
Main PC Compressor Oil Info Page

Order Online in the store or call for better rates on case and larger sizes. Download the full details on AMSOIL PC Series Compressor Oils.
Compressor Oil Cross-Reference and total information guide. – Use this for the latest information on the compressor oils from the factory.

SIROCCO™ Synthetic Compressor Oil

AMSOIL SIROCCO® Synthetic Ester Compressor Oil has higher flash, fire and auto ignition points than competitive petroleum oils. Its resistance to carbon formation and the ashless additive system minimize the incidence of deposits acting as ignition-promoting hot spots. Although AMSOIL SIROCCO® Synthetic Compressor Oil increases fire safety, it cannot be considered nonflammable.
ISO 32/46 (SEI)

AMSOIL SIROCCO® Synthetic Compressor Oil (SEI) is recommended as a direct replacement for PAG compressor oils such as Sullair Sullube 32® and Ingersoll-Rand SSR Ultra-coolant®. Not recommended for use with Silicone base fluids.

AMSOIL SIROCCO® Synthetic Compressor Oil is formulated with premium synthetic ester technology. This high-quality, long-life fluid lasts several times longer in use than mineral-based oils. AMSOIL SIROCCO Compressor Oil is fully formulated with non-detergent additives and is designed for use in rotary screw compressors and vacuum pumps. SIROCCO effectively protects against wear, oxidation, foam and rust. Its inherent lubricity and good thermal conductivity allow it to reduce heat and energy consumption. AMSOIL SIROCCO Synthetic Compressor Oil increases operating efficiency, reducing energy and maintenance costs. AMSOIL SIROCCO maintains performance across a wide operating temperature range. Its low pour point, high viscosity index and lack of paraffins (wax) make it an excellent all-season lubricant. At cold temperatures, equipment starts easier and the lubricant is quickly pumped to critical components, preventing lubricant starvation and excessive wear. SIROCCO also repels water to prevent damaging oil/water emulsions, allowing for longer lubricant life and ease of water removal from the reservoir.
Order Online in the store or call for better rates on case and larger sizes as most of our SEI customers require drum sizes. Call 800-579-0580  for more info. 

DC Series Synthetic Ester Compressor Oils

Call before ordering DC series compressor oils.
ISO 100 & 150
AMSOIL DC Synthetic Compressor Oils are long-life, premium compressor lubricants based on novel, proprietary technology. They improve compressor efficiency
and extend drain intervals in reciprocating (piston) compressors and vacuum pumps where high discharge temperatures or carbon build-up are a concern.
AMSOIL DC Synthetic Compressor Oils incorporate the highest quality, thermally-stable synthetic esters fortified with premium non-detergent, ashless additives for maximum protection at high temperatures and pressures where petroleum lubricants typically break down.

AMSOIL DC Series Synthetic Compressor Oil can be used in reciprocating and vane compressors and vacuum pumps.

Call 800-579-0580   (not available locally – ships from the Wisconsin HQ.)

What parameters are our Compressor Oils tested by?


Compressed air is a critical part of many manufacturing facilities; without it, production would cease. Reliable air compressor operation is essential to manufacturing production. Lubrication is key to keeping air compressors running and is sometimes called the compressor’s “life-blood.” Compressor lubricants are produced by many lubricant manufacturers, ranging in quality from poor to excellent. Poor air compressor oil could cause the compressor to have a very short life, but excellent quality air compressor oil reduces maintenance and can extend compressor life. Some end users find comfort in using the manufacturer recommended oil because of perceived quality.

The American Petroleum Institute (API) governs the minimum quality standards for engine oils. Air compressor oils are not governed by any organization, so no official performance standards exist. This leaves the responsibility for producing a satisfactory product to the individual lubricant manufacturers.

Air compressor original equipment manufacturers (OEM) help eliminate some confusion by publishing minimum oil specifications required for their individual air compressors. These minimum oil specifications insure minimum lubricant performance. Any oil that meets or exceeds the minimum specifications can be used without voiding the standard or regular compressor warranty (usually one or two years).While OEMs do not manufacture their own compressor oil, they frequently market their own brand of compressor oil and have often been able to tie separately purchased extended warranty requirements to the use of their own branded oil.

Air compressor companies must contract with a lubricant company to manufacture oil for them. When the air compressor manufacturers purchase oil from a lubricant manufacturer they become the middlemen and the cost is increased to the consumer. OEM branded compressor oils provide the allure of quality, but in many cases the price of these oils is unnecessarily inflated and is frequently exorbitant. In addition, these oils often do not have the best performance characteristics that are available on the market.

Test Methods
The testing by which these oils are evaluated is done in accordance with American Society for Testing and Materials (ASTM) procedures. The results of these tests can be duplicated and verified by laboratories that conduct these ASTM tests. A notarized affidavit certifying the results are correct is included in the appendix. Compressor oil pricing was determined by contacting the manufacturer or the distributor and requesting a quote on a five-gallon pail and a fifty-five gallon drum of their lubricant.

This information is focused on the stresses of rotary screw type compressor oils. Rotary screw compressors are widely used in all types of industries, and synthetic compressor oils are recognized as superior to mineral-based compressor oils by compressor manufacturers as well as most oil companies and consumers.

Desired Performance Characteristics and Results

Oils used in rotary screw compressors operate in severe environments. In order to list the desired performance characteristics of compressor oils, it is important to first understand the environment the oil must withstand inside the screw compressor. Air enters the compressor through an air intake filter. The air compressor oil is injected into the compressor and is compressed with the air. During the air compression process heat is generated and small amounts of moisture contained in the air mix with the oil. Moisture, when mixed with oil, can cause oil water emulsions, rust and foaming. The compressed air/oil mixture then enters the air/oil separator where the hot oil and air are separated by the oil separator element.
The compressed hot air then goes through a cooler, where the moisture in the air condenses and can be drained off. The air then goes to the plant to run production equipment. The hot oil goes through the oil cooler and is then injected back into the compressor once again.
This process can be continuous for up to 8,000 hours or more. Oil degradation can result in acid buildup, hydrolysis and oxidation. Through the compression process the oil is expected to provide the following functions:

  • Oxidation resistance from the heated air/oil compression
  • Resist acid buildup due to oxidation from extended oil drain intervals, moisture and heat
  • Exhibit good demulsibility to separate the water from the oil
  • Prevent against internal rust formation
  • Resist foaming
  • Control air entrainment
  • Reduce wear
  • Maintain viscosity parameters
  • Extend oil drain intervals
  • Provide low temperature fluidity protection

Rotory Screw Compressor Oils must remain stable without foaming and loss of viscosity.

Oxidation Resistance

The high-speed rotors in rotary screw air compressors compress large volumes of air. At the same time, oil is injected into the rotors to lubricate the moving parts during compression. The hot oil and air mixture can increase the rate of lubricant degradation through oxidation. The evaluated oils were subjected to the Rotating Pressure Vessel Oxidation Test in order to simulate air compressor oil oxidation while in service.

Rotating Pressure Vessel Oxidation Test (RPVOT) ASTM D-2272

The Rotating Pressure Vessel Oxidation Test is a rapid method of comparing the oxidation life of new or in-service lubricants. The vessel is initially charged with 50 grams of test oil and five grams of distilled water. A copper catalyst is added, and the vessel is pressurized with oxygen to 90 PSI at room temperature and submerged into a 150° C (302° F) temperature bath. The bath temperature causes this pressure to increase to approximately 200 PSI. The vessel is rotated and as oxygen is absorbed into the oil from oxidation, a pressure drop occurs. The failure point is taken as a 25-PSI drop from the maximum pressure attained at 150° C (302° F). The results are reported as the number of minutes until a 25-PSI loss occurs.

Correlation to Field Service

The Rotating Pressure Vessel Oxidation Test (RPVOT) is useful in estimating the oxidation stability of oils. The RPVOT can also be used to compare new oils to provide a correlation between the RPVOT value and an oil’s useful life before oxidation occurs. A high RPVOT number correlates to high oxidation resistance and long oil life. A low RPVOT number correlates to low resistance to oxidation and short oil life.

Water Resistance

When air or process gases are compressed, moisture from humidity condenses and collects in the oil, creating the need for the oil to have good hydrolytic stability. Good hydrolytic stability is important as this helps prevent oil degradation from hydrolysis, which forms acids and contributes to foaming.

Hydrolytic Stability ASTM D-2619
This test is used to determine the stability of oils in contact with water. It depends upon the catalytic effect of copper at elevated temperatures in the presence of water to accelerate the rate of hydrolysis. This test is conducted by incorporating 75 grams of test oil along with 25 grams of water and a polished, weighed copper strip catalyst sealed in a six-ounce pressure-type beverage bottle. The bottle is rotated at five rpm, end over end, for 48 hours in an oven at 93.5° C (200° F).

At test end, the four most important results were evaluated.

  1. Acidity of water layer
  2. Appearance of copper panel
  3. Weight change of copper panel
  4. Percent change in oil viscosity

Acidity of Water Layer
Generally oil analysis laboratories flag the acidity of air compressor oil when the acid number is greater than 2.0 to 2.5 above the new oil acid value. Acidic air compressor oil can shorten the oil life and corrode internal parts. Since acid increase in the water layer can affect the acidity of the oil, lower acidity of the water layer is desirable. The following chart identifies the acidity of the water layer for the oils tested. The values are listed as milligrams of potassium hydroxide (mg KOH) required to neutralize all acidic constituents present in one gram of sample.

The Appearance of the Copper Panel

All but one of the oils recorded good copper panel values of shiny 1B. Atlas Cop co HD-Rotofluid was not as good and recorded a value of shiny 3B. The ASTM copper panel test scale is, from best to worst, 1A, 1B, 2A, 2B, 2C, 2D, 2E, 3A, 3B, 4A, and 4C.

Weight Change of Copper Panel

Copper panels were weighed before the test and then again after the test. The difference in copper weight is the loss of copper due to corrosion. Three oils recorded a value of 0.000 mg/cm 2 and exhibit no corrosiveness to the copper panels. All other oils tested recorded copper loss due to corrosion. Copper loss due to corrosion is much the same as copper loss due to rubbing wear and is equally destructive.

 Percent Change in Viscosity

Most air compressor manufacturers recommend oil viscosity of ISO-46. ISO-46 viscosity is measured in centistokes (cSt), and the cSt range is 41.4 to 50.6. Significant increases or decreases in viscosity are undesirable as they can contribute to greater energy consumption or increased wear.

Water Emulsion

Water contamination in rotary screw compressors can develop from large amounts of ingested air containing small amounts of moisture. This moisture can build up and cause water/oil emulsions causing shortened oil drain intervals.

Demulsibility ASTM D-1401

The demulsibility test is used to determine the ability of oil such as air compressor oil to separate from water. In this test, 40 ml of distilled water and 40 ml of oil are measured into a properly cleaned 100 ml graduated cylinder and immersed in a bath at 54.4° C (130° F). The oil and water are mixed for five minutes at 1500 rpm with a special stirrer. The amounts of separated oil, water and emulsion are recorded at five-minute intervals for up to one hour, then reported as ml oil/ml water/ml emulsion (minutes). Most specifications require separation, so that less than three ml of emulsion (cuff) remain after 30 minutes.

Correlation to Field Service

Emulsification of air compressor oil can cause sludge, plug filters, shorten oil life, cause foaming and reduce lubricant performance. it is important for air compressor oil to maintain good demulsibility in order for excess water to be drained off. Complete demulsibility minimizes environmental discharge.

Internal Component Rusting

Oil in its neat state, without additives, does a poor job of preventing rust. In many instances, such as in air compressors, water can become mixed with the lubricant and rusting of ferrous parts can occur. The air compressor oil needs to be formulated with additives that will inhibit the formation of rust. Rust is very abrasive and once formed on bearings and critical components it will significantly shorten component life. The ASTM rust test was developed as an evaluation of the oil’s ability to aid in preventing rust.

Rust Prevention in Synthetic Sea Water ASTM D-665B

The test consists of stirring a mixture of 300 ml of water, either distilled or seawater, at 60° C (140° F) for 24 hours. A special cylindrical steel test specimen made from #1028 cold finished carbon steel is polished and then completely immersed in the test fluid. At the conclusion of the 24-hour period the specimen is removed, washed with solvent and rated for rust. In order to pass the ASTM D-665 Rust Test, the specimen must be completely free from visible rust when examined without magnification under normal light.When conducted in synthetic seawater, this test is more severe than in distilled water. It helps identify the oils with superior rust protection.

Correlation to Field Service

Internal component rusting can flake off and contaminate the oil causing filter plugging, increased wear and shortened oil life.


The oil in a rotary screw compressor experiences severe air/oil churning, therefore foaming of the oil is likely to occur. The tendency of compressor oil to foam can be a serious problem in screw-type air compressors. In these situations, increased wear and shortened oil life is likely to occur.

Foam Stability ASTMD-892

This ASTM test consists of a 1000 ml graduated cylinder, 200 ml of oil and an air inlet tube which is fastened to a gas diffuser placed at the bottom. Air flows through the diffuser at a rate of 94 ml/min. The test is conducted in three sequences.

  1. Sequence I is conducted at 24° C (75° F)
  2. Sequence II is conducted at 93.5° C (200° F)
  3. Sequence III is conducted at 24° C (75° F)

The foam results are reported in milliliters (ml) of foam during the test and after 10 minutes settling time.

Correlation to Field Service

Foam causes increased oxidation by exposing more of the oil surface area to oxygen. Foam also increases heat by acting like a blanket and not allowing the oil to dissipate the heat. Foam reduces the lubricating qualities of oil when the bubbles entrained in the oil collapse, reducing the oil film in critical areas and resulting in less than full-film lubrication. Oils that foam during the test could exhibit a tendency to foam inside the compressor during operation. Oil that still contains foam after 10 minutes of settling time exhibits very poor antifoaming ability.

Wear Reduction

Wear reduction is one of the most important qualities sought after by consumers of all types of equipment including air compressors. In order to extend air compressor component life, some lubricant manufacturers have incorporated anti-wear chemistries into their oils. Anti-wear chemistries are not used in all compressor oils. Since the choice to use anti-wear chemistries is left to the oil manufacturers, and many have chosen to incorporate it, the anti-wear performance of each was measured. The ASTM D-4172 4-Ball wear test is widely used to determine anti-wear fluid qualities and is the test of choice for air compressor oil comparisons.

Wear Preventative Characteristics of Lubricating Fluid ASTM D-4172 (4-Ball Method)

This test method is used to determine the anti-wear or wear preventive properties of a fluid. It is conducted with three steel balls clamped together and covered with the lubricant to be evaluated. The fourth ball is pressed with force into the cavity formed by the three balls clamped together. The temperature of the test lubricant is regulated and the fourth ball is rotated. Wear is measured in millimeters by calculating the average wear scars of the three lower clamped balls. Standard ASTM test parameters of 75° C (167° F), 1200 RPM and 40 Kg of force were used.

Correlation to Field Service

Low wear scar measured by millimeters in the 4-Ball wear test correlates to better anti-wear oil qualities. A low wear rate in-service can extend oil life, reduce maintenance, extend equipment life and reduce maintenance costs.

Copper Corrosion ASTM D-130

Corrosion resistance is an important consideration in compressor oils. Copper corrosion characteristics were measured using the ASTM D-130 test. This test operates for three hours at 100 ° C (212° F) with a copper strip submerged in the candidate oil.

Entrained Air

Agitation of lubricating oil in air compressors can cause air entrainment. Air entrained oil contains finely divided air bubbles in the oil that reduce the lubricating quality in service.

Air Release ASTM D-3427

The air release test determines the ability of oil to separate entrained air. In the test, compressed air is blown through the test oil, which has been heated to a temperature of 50°C (122° F). After the airflow is stopped, the time required for the entrained air to reduce in volume to 0.2% is recorded as the air release time.

Correlation to Field Service

In order to lubricate and cool rotary screw air compressors, oil is injected directly into the rotary screws and mixed with the air. This can cause air entrainment, which can cause an inability to maintain oil pressure, reduce oil films on bearings, increase wear and cause poor air compressor performance. A short air release time is desirable.

 Physical Data

Three areas of physical data have been included to describe the important properties of the various oils. This data provides an indication of performance in certain areas such as viscosity change with temperature change, viscosity and cold temperature operation.

Viscosity Index ASTM D-2270

Viscosity Index (VI) indicates the degree of change in viscosity of an oil within a given temperature range. High VI reflects a relatively small change in viscosity, whereas a low VI reflects a larger change in viscosity. High viscosity index is more desirable for air compressors and will result in less oil thickening at cold temperatures as well as less thinning at higher temperatures.

Correlation to Field Service

High viscosity index will provide air compressor oil with viscosity stability over a wider temperature range, providing better protection in high temperatures as well as better oil flow at lower temperatures.

 Viscosity at 40° C ASTM D-445

Air compressor manufacturers recommend specific viscosity grades based on the International Organization for Standardization (ISO). The most common viscosity grade for rotary screw air compressors is ISO-46. According to the ISO, viscosity is measured in centistokes (cSt) and the acceptable viscosity range for ISO-46 oil is 41.1 cSt to 50.6 cSt. Viscosity is measured and recorded at 40° C (104° F).

Correlation to Field Service

Correct viscosity is important based on the compressor manufacturer’s recommended viscosity at given temperatures.

Pour Point ASTM D-97

Pour point is a physical measurement of the oil’s fluidity at cold temperatures. This test provides the temperature at which oil will no longer flow. Typically, 11° C (20° F) above the pour point is the recommended limit at which a compressor can be safely started for operation. Oil starvation could occur at colder temperatures and result in equipment damage.

Correlation to Field Service

Air compressors are sometimes installed outside to control noise and gain manufacturing floor space. Installing the air compressor outside subjects the compressor to cold winter temperatures, which can thicken some oils to the point of becoming solid and causing compressor damage.


Paying a high price for air compressor oil does not necessarily mean getting the best quality. Purchasing air compressor oil should include choosing an overall high quality product at the lowest price obtainable. This will insure getting the best value for your investment. Call for current price. We consistantly beat our competition on price!

It is important to have a balanced air compressor oil that will perform all functions well. AMSOIL PCI demonstrated excellent performance and is a well-balanced oil that delivers consistent, dependable air compressor operation.

For more information regarding AMSOIL PCI Synthetic Compressor Oil, contact Ches Cain at 605-274-2580.