Sinclair Monograde Heavy Duty Diesel Engine Oil

Heavy Duty Engine Oil

Advanced Oils for Engines of Advanced Age

Your engine has served you well over the years. Now it’s your turn to serve it with outstanding protection that strikes just the right mix of durability, longer drain intervals and protection of emissions control devices.

Sinclair Monograde Heavy Duty Diesel Engine Oil: Performance You'll Notice

Sinclair leans on over 100 years of lubrication knowledge to bring you a tough, enduring level of protection that reduces contact between metal parts and keeps friction at a minimum, giving you:


Outstanding performance for extended drain intervals, with up 1.6% improved fuel mileage with HD 10W-30 grade.


Increased wear protection of up to 53%.


Deposit control up to 63% and better oxidation control up to 83%.

Typical Properties

Viscosity Grade HD SAE 30
Color ASTM D1500 2.5
Flash Point °C ASTM D92 208
Flash Point °F ASTM D92 406
Gravity, °API ASTM D287 30.03
Pour Point °C (°F) ASTM D5950 -30°C (-22°F)
Specific Gravity @ 60°F (15.6°C) ASTM D4052 0.876
Viscosity @ 100°C cSt ASTM D445 10.91
Viscosity @ 40°C cSt ASTM D445 91.05
Viscosity Index ASTM D2270 105
Zinc, wt. % ASTM D5185 0.086

Industry/OEM Approvals

Title HD SAE 30
API CF Meets Requirements
API CF-2 Meets Requirements
API SN Plus Approved