Shell Corena S4 P 68
Shell Corena S4 P 68 is an advanced synthetic air compressor lubricant designed specifically for reciprocating (piston) air compressors operating under severe conditions. Formulated using high-performance synthetic ester base fluids and a unique additive system, the oil delivers outstanding thermal stability, excellent wear protection and extended service life in demanding industrial compressor applications.
A key advantage of Shell Corena S4 P 68 is its ability to maintain reliable lubrication under extremely high temperatures and pressures. The oil is engineered for compressors operating with discharge temperatures exceeding 220°C and under continuous high delivery pressures. Its synthetic ester formulation offers superior resistance to oxidation and thermal breakdown compared with conventional mineral compressor oils, ensuring stable performance in harsh operating environments.
The lubricant also provides exceptional deposit control. Shell Corena S4 P 68 helps prevent the formation of carbon deposits and lacquer on valves and piston crowns at elevated operating temperatures. These deposits can reduce compressor efficiency and increase maintenance requirements. By maintaining clean internal compressor components, the oil supports reliable compressor performance and improved operational efficiency over extended service periods.
Shell Corena S4 P 68 can significantly extend maintenance intervals in reciprocating compressor systems. In many cases, valve maintenance intervals can be extended from around 1,000 operating hours with conventional mineral oils to between 2,000 and 4,000 hours depending on compressor design and operating conditions. This helps reduce maintenance costs and minimise operational downtime.
The formulation also delivers outstanding wear and corrosion protection. It protects internal compressor components such as bearings and gears from corrosion and mechanical wear, helping extend equipment life. In addition, its excellent water separation capability allows condensate to separate easily from the oil, helping prevent corrosion and maintain efficient compressor operation.
Shell Corena S4 P 68 also contributes to improved air line safety. By minimising the formation of carbonaceous deposits in compressor discharge systems, it helps reduce the potential for reactions between deposits, rust particles and compressed air heat that could otherwise lead to fire or explosion risks in discharge air lines.
The product is recommended for industrial reciprocating air compressors operating under severe conditions, particularly those with air discharge temperatures above 220°C and continuous high delivery pressures. It can also be used in breathing air compressors when appropriate air clean-up systems are installed to ensure breathable air quality.
Typical physical characteristics include ISO viscosity grade 68, kinematic viscosity of 68 mm²/s at 40°C and 8.5 mm²/s at 100°C. The oil has a density of 990 kg/m³ at 15°C, flash point of 250°C and an excellent low-temperature pour point of –51°C. Sulphated ash content is less than 0.02%, and the oil passes ASTM D665A rust prevention testing. Water separability at 54°C is approximately 30 minutes.
Shell Corena S4 P 68 meets DIN 51506 VDL severe-duty compressor oil specification, ISO 6743-3 L-DAB classification and EN 12021 requirements.
