Dark blue grease is often referred to as blue moly grease. It is a specialised lubricant that plays a role in heavy-duty applications, which standard greases are not sufficient for.
This is a solid lubricant that provides exceptional performance under extreme pressure conditions. The distinctive blue colouration comes from the addition of molybdenum disulfide (MoSâ‚‚).
In this article, we will discuss the characteristics, specific applications and advantages of dark blue grease.
The composition and properties of dark blue grease
Dark blue grease – manufactured by various big name brands including Mobil and Castrol – usually contains a synthetic or semi-synthetic base oil combined with complex soap thickeners and molybdenum disulfide. This creates a lubricant with good stability across a wide temperature range – typically from -20°F to 430°F.
Thanks to the molybdenum particles in its composition, dark blue grease provides a secondary lubrication function that can protect metal even when heavy loads have worn the base oil film formed by the lubricant.
Due to this characteristic, dark blue grease is especially suited to high-stress applications, compared to standard lubricants.
Dark blue grease for heavy equipment applications
Heavy equipment operators rely on dark blue grease for articulated joints on excavators, bulldozers and front-end loaders. In these applications, large forces are concentrated on small bearing surfaces, making regular lubrication insufficient for the task.
Dark blue grease for marine applications
Dark blue grease also offers excellent water resistance, which makes it particularly suitable for marine applications.
It is used on boat trailer wheel bearings, outboard motor components and dock equipment to provide effective lubrication even when submerged. The molybdenum in its composition helps to protect against corrosion caused by saltwater.
Industrial uses of dark blue grease
In industrial settings, dark blue grease excels in applications involving slow-moving, heavily loaded bearings and gears.
Mining equipment, steel mill machinery and paper processing plants utilise dark blue grease for demanding lubrication points. It can withstand extreme pressures without being squeezed out of the bearing surfaces; this ensures continuous protection even under shock loading conditions.
Many industrial maintenance programs require dark blue grease to guard against equipment failure that would result in costly downtime, or where there is limited access for relubrication.
Application considerations
When using dark blue grease, technicians should be aware that it should not be mixed with other grease types, as this can lead to unpredictable performance.
