AMSOIL ISO 68 100% Synthetic Compressor Oil
AMSOIL ISO 68 100% Synthetic Compressor Oil (PCJ) is the SAE 30 viscosity in the AMSOIL PC Series family, built on thermally stable synthetic base oils and a non-detergent additive system for hot-running rotary screw, reciprocating, vane, and centrifugal compressors. The heavier ISO VG 68 grade fits warm-climate shops, sustained high-load duty cycles, and older machines that need a thicker oil film for sealing and oil carry-over control.
Long fluid life in rotary screw service
PC Series Synthetic Compressor Oil supports drain intervals of up to 8,000 hours in rotary screw compressors under normal operation at 200 F oil discharge temperature, subject to operating conditions and oil analysis monitoring. Synthetic base oils resist the oxidation and viscosity shear-thinning that push petroleum compressor oils into early changes, reducing downtime and waste-oil disposal volume for shop, fleet, and industrial users.
Superior varnish resistance under heat
Varnish is a leading cause of efficiency loss and mechanical failure in high-temperature compressor service. In comparison testing of AMSOIL PC Series Synthetic Compressor Oil (PCI, ISO 46) against a leading competitor synthetic compressor oil in industrial rotary-screw compressors at 200 F oil discharge, evaluated using the Membrane Patch Colorimetry Test (ASTM D7843), the competing oil reached critical varnish potential after only 6,228 hours of service while PC Series continued to show ultra-low varnish potential after 8,000 hours. The PCJ ISO 68 grade uses the same PC Series antioxidant and thermal-stability package in a heavier-viscosity formulation.
Reduced oil consumption and tight foam control
Excessive oil consumption forces frequent top-offs that waste labor and lubricant budget. In comparison testing of AMSOIL PC Series Synthetic Compressor Oil (PCI, ISO 46) against a leading competitor synthetic compressor oil for 8,000 hours in an industrial rotary-screw compressor under matched operating conditions, the foam resistance and air-release behavior of PC Series helped reduce oil consumption by 35 percent. The PCJ ISO 68 grade meets the ASTM D892 Sequence I, II, and III foam test with 0/0 readings across all three sequences, so air entrainment stays low and discharge volumes stay stable.
Wear, water, and corrosion control
Anti-wear additives keep metal-to-metal contact in check at bearings, vanes, gears, and ring belts. The PCJ ISO 68 grade records a 0.41 mm scar in the Four-Ball Wear Test (ASTM D4172, 40 kg, 1,200 rpm, 75 C, 1 hour). PC Series is also anti-rust fortified and hydrolytically stable, separating readily from condensate water (ASTM D1401 demulsibility 40/40/0 in 15 minutes), passing both rust tests (ASTM D665 A and B), and earning a 1A rating in the Copper Strip Corrosion Test (ASTM D130) to protect bronze and copper alloys common in compressor crankcases and oil coolers.
Heat, oxidation, and safety profile
Specialized antioxidants resist varnish, carbon, and acid formation so the oil holds up longer in service than petroleum compressor oil, especially at high discharge temperatures. PC Series is an ashless, high-flash-point formulation with very low carbon-forming tendencies that minimizes ignition-promoting hot spots in discharge lines. The ISO 68 grade reaches a flash point of 260 C (500 F) and a fire point of 284 C (543 F), with a pour point of -37 C (-35 F). PC Series is not a fire-resistant oil and is not approved for breathing-air or refrigeration compressor service.
Recommended applications and service intervals
ISO 68 100% Synthetic Compressor Oil (PCJ) is the heavier-viscosity option in the PC Series family. It is built for higher ambient temperatures, larger reciprocating compressors, and rotary screw compressors that benefit from a thicker film for sealing and oil carry-over control. Use the appropriate viscosity of PC Series in the following applications and within the listed service-life caps:
- Single and multistage rotary screw, vane, centrifugal, and reciprocating compressor crankcases and cylinders, vacuum pumps, pressure washer pumps, blowers, gears, bearings, and pumps. Drain intervals of up to 8,000 hours can be expected under normal operation in rotary screw compressors at 200 F oil discharge temperature.
- Match grade to duty: PCH ISO 32, PCI ISO 46, and PCJ ISO 68 are listed for rotary compressors at 32 to 68 cSt; PCJ ISO 68 and PCK ISO 100 are listed for reciprocating compressors at 68 to 100 cSt.
- Not recommended for breathing-air or refrigeration compressors, polycarbonate or PVC plastics, butyl rubber, ethylene-propylene rubber, or SBR rubber. Not compatible with polyalkylene glycol or silicone oils.
- Outside the United States and Canada, confirm OEM compatibility with the equipment manufacturer or AMSOIL Technical Services before installation.
Periodic oil analysis is recommended for any extended-drain program, with service intervals governed by the equipment manufacturer schedule and the trend data. PC Series ISO 68 is compatible with petroleum oils and most synthetic oils, seals, paints, and materials, but for best results flush old oil, remove carbon deposits per the manufacturer procedure, and change all oil filters before installation. Aftermarket additives are not recommended.
Typical technical properties
| Property | Value |
|---|
| ISO Viscosity Grade (ASTM D2422) | 68 |
| SAE Grade | 30 |
| Kinematic Viscosity at 100 C, cSt (ASTM D445) | 10.2 |
| Kinematic Viscosity at 40 C, cSt (ASTM D445) | 66.6 |
| Viscosity Index (ASTM D2270) | 138 |
| Specific Gravity (ASTM D1298) | 0.8597 |
| Density, lbs/gal (ASTM D1298) | 7.16 |
| Flash Point, C (F) (ASTM D92) | 260 (500) |
| Fire Point, C (F) (ASTM D92) | 284 (543) |
| Pour Point, C (F) (ASTM D97) | -37 (-35) |
| Four-Ball Wear Test scar, mm (ASTM D4172) | 0.41 |
| Copper Strip Corrosion (ASTM D130) | 1A |
| Rust Tests, fresh and synthetic sea water (ASTM D665 A and B) | Pass |
| Foam, Sequence I, II, III (ASTM D892) | 0/0, 0/0, 0/0 |
| Demulsibility, oil/water/cuff in minutes (ASTM D1401) | 40/40/0 (15) |
Order AMSOIL ISO 68 100% Synthetic Compressor Oil
AMSOIL ISO 68 100% Synthetic Compressor Oil is available in 5 Gallon Pail (PCJ05-EA), 55 Gallon Drum (PCJ55-EA), and 275 Gallon Tote (PCJ27-EA) sizes for shop, fleet, and industrial accounts. AMSOIL products are backed by the AMSOIL Limited Liability Warranty. Compare ISO 32, 46, 68, and 100 grades and match the right viscosity to the compressor duty cycle in the Compressor Oil Guide, confirm equipment application match in the AMSOIL Vehicle Lookup Guide, then order AMSOIL ISO 68 100% Synthetic Compressor Oil.
Customer reviews
Reasonably priced synthetic compressor oil
As advertised. The only down side is that they don’t sell on Amazon or provide free shipping.
By Brent from Florida on February 22, 2026.
Would recommend this to a friend.
Compressor oil
Good stuff never had a problem
By Brian from Tennessee on December 29, 2025.
Would recommend this to a friend.
Use in my Tuthill Blower
Been using this for years to maintain my blower, I won't use anything else
By Tim from TX on November 27, 2025.
Would recommend this to a friend.
Read all 57 reviews
Frequently asked questions
What is synthetic compressor oil and why use it instead of motor oil?
Synthetic compressor oil is a non-detergent industrial lubricant formulated for the high-temperature, oxygen-rich service inside reciprocating and rotary screw compressors. PC Series ISO 68 uses thermally stable synthetic base oils and antioxidant chemistry tuned for compressor duty, while detergent automotive motor oil is built for combustion-engine soot loading and can foam, oxidize, and form varnish faster in compressor service.
Is ISO 68 the right viscosity for a shop air compressor?
The right ISO grade depends on the compressor manufacturer recommendation, ambient operating temperature, and compressor type. ISO 68 is generally specified for hot-climate shops, larger reciprocating compressors, and rotary screw compressors that benefit from a thicker oil film for sealing and oil carry-over control. Lighter ISO 32 or ISO 46 grades are common for cooler ambient conditions and smaller rotary screw machines. Compare ISO grades side by side in the Compressor Oil Guide.
How long does PC Series ISO 68 last in a rotary screw compressor?
Drain intervals of up to 8,000 hours can be expected in rotary screw compressors operating at 200 F oil discharge under normal conditions. Real-world life depends on oil discharge temperature, ambient conditions, ingestion of dust or moisture, and filter and separator condition. Verifying with periodic oil analysis is recommended for any extended-drain schedule.
Can PC Series ISO 68 be used in a reciprocating piston compressor?
Yes. PC Series ISO 68 (PCJ) and ISO 100 (PCK) are listed for reciprocating compressor crankcases and cylinders. PCJ is also approved for vacuum pumps, pressure washer pumps, blowers, gears, bearings, and pumps. PC Series is not approved for breathing-air or refrigeration compressor service.
Will PC Series mix with the petroleum oil already in the compressor?
PC Series is compatible with petroleum oils and most synthetic oils, seals, paints, and materials, so accidental top-offs will not damage the system. For full extended-drain service life, drain old oil, remove carbon deposits per the compressor manufacturer procedure, change all filters, and refill with PC Series. PC Series is not compatible with polyalkylene glycol or silicone-based compressor oils.
Does PC Series carry a warranty?
Yes. AMSOIL products are backed by the AMSOIL Limited Liability Warranty. Coverage details are available in the AMSOIL warranty document linked from the product page.
