How to Choose the Right Grease for Heavy Equipment

An all-purpose grease isn’t always the right choice. Does your grease make the grade?

Just as joint fluid allows us to bend at the elbow, hips, shoulders and knees without bones grinding against each other, oil and grease prevent the metal-on-metal grinding of moving parts of heavy equipment.

Greasing your machines properly can extend the life of the equipment and help you get the best performance out of it. And it means not just greasing regularly but also using the right grease.

RELATED: The Importance of Greasing Your Machines

Some contractors prefer to stick with one type of grease for the sake of convenience and inventory, but not all greases are created equal. When choosing a grease, start with the recommendations in the owner’s manual, if there are any (if they exist, they are often vague). Then keep these tips in mind to make sure your grease makes the grade.

Match the grease to the season

Grease comes in different levels of viscosity, or thickness. Grease with the highest viscosity does well in the summer, as it tends to thin out during hot weather use. Greases with lower oil viscosity can perform well in the winter.  

Synthetic grease is an option for both cold and heat as it is resistant to extreme temperature.

Consider a different grease for extreme pressure

Many pieces of heavy equipment are designed to engage in extreme pressure operations, like those involving heavy stress and shock loading. For these applications, some manufacturers recommend a grease with a molybdenum disulfide, or "moly," additive. The moly gets into even the tiniest machining marks on pins and bushings, preventing them from making contact with each other.

Use different greases for different parts

The temperature of a machine's working parts also comes into play. Brakes that experience periods of high operating temperatures but remain mostly cool otherwise can get by with a less viscous grease than parts that maintain consistently high levels of heat during operations. Synthetic grease is the best choice for those applications.

Choose marine grease for wet conditions

For work that requires steady machine exposure to wet conditions, marine grease is often the best choice. Some are made with lithium complex thickeners, but all will protect parts from both salt and fresh water. As a bonus, most marine greases will also protect machines during extreme pressure uses.

Purge before switching

Before using a new grease, the old grease may need to be purged, or removed totally from the equipment, due to incompatibility between certain greases. This purging can be accomplished through a combination of degreasing and pressure washing.

Greasing machines properly to help them last longer?

Now that’s a slick move.

WATCH: Quick Tips on Greasing Maintenance

Visit the United Rentals marketplace to rent equipment today and find tools you need for a better worksite.

Was this article helpful?