The Importance of Water Resistance in Lubricating Greases

Noria Corporation

No matter what industry you find yourself in, there are certain characteristics that will remain constant. One of those is the risk of water contamination. Water can come into contact with your machines in a variety of ways. Some machines even have the capability of producing water on their own. Because water can affect a machine’s remaining useful life and performance, it is important to have a quality heavy-duty grease that has the ability to protect your machines against water contaminants. This article will help you understand why it is important to have a water-resistant grease and how to select the right one for your needs.

How Water Causes Machine Failure

The presence of water in machinery can have a severe impact on your machine components. Surface corrosion, or surface pitting, is one common problem. Water has also been directly linked to causing accelerated surface fatigue, especially in bearings, through cavitation and hydrogen embrittlement. Other impacts that water can have on a machine include reduced lubricating effectiveness, such as decreased lubricant film thickness and reduced load-carrying abilities, all of which contributes to increased machine wear and the potential for machine failure.

Why to Choose a Water-Resistant Grease

It’s important that your heavy-duty grease be resistant to water. Your equipment comes into constant contact with water from multiple sources, such as routine cleaning, the environment, and even the machines themselves. For your machines to continue operating at peak performance under all circumstances, it’s important that your selected grease can protect machines against all forms of water contamination.

Water is frequently considered one of the most common contaminants that can cause damage to your machinery, and there are several ways that water can get into your equipment and wreak havoc. But no matter how it gets in, water can lead to costly outcomes such as corrosion, leakage, oxidation, and oil flow restriction.

Water is one contaminant that can affect any industry sector, from mining to agriculture and even food production, while having the potential to impact any machine, from bulldozers and excavators to fleet trucks. That’s why it is imperative to have a high-quality grease that focuses on water resistance to help prevent premature failure and expensive repair costs.

Water-Resistant Grease Characteristics

There are several key characteristics that should be looked at when choosing the right heavy-duty grease. The most important aspect is the grease’s water solubility and how it reacts with water. This plays into a particular concern for many industrial plants – how to prevent free water, which can cause corrosion and bearing failure.

This is why it’s imperative to have a heavy-duty grease that inhibits the formation of free water. In situations like these, a quality water-resistant grease with good sealing capabilities is highly coveted.

The next characteristic to look for is the grease’s maximum water absorption potential. Unlike their oil counterpart, greases can absorb a certain amount of water that would otherwise get into your machines and cause damage. When the water is absorbed by the grease, it does one of three things – dissolves, emulsifies, or becomes free.

When water is dissolved, there is no change in the grease. As the grease gets near its saturation point, or the point when no more water can be absorbed, the water must be emulsified to be absorbed. This means that the water must be broken down into small droplets through agitation before it can hope to be absorbed. Finally, free water occurs when no more water can be absorbed. By reducing the grease’s film strength and causing corrosive damage, it is the emulsified and free waters that pose the greatest risk to machine health.

It is also important to have a heavy-duty, water-resistant grease for bearings that are going to be operating at higher speeds. Because of their continually elevated speed, they are not able to hold as much grease without potentially overfilling the part. Therefore, they rely on the grease to act as a shield to prevent water from coming through. In this instance, you want a grease that can absorb a significant amount of water while still functioning at an optimal level.

Testing Water-Resistant Greases

But how do you know if the heavy-duty grease you’ve selected is going to be the best option for your needs? You look at how they perform during different testing methods.

The first test to look at is the water washout test. It measures how a particular grease resists the effects of water, prevents failure, and increases service life. The next test is the water spray-off test, which measures how the grease stays in place when exposed to direct water spray while on a flat surface. If the grease is able to stay in place, it indicates that the grease will prevent dry spots, which can lead to rust and corrosion. The final test is a penetration test to measure a grease’s consistency. Consistency is a grease’s ability to resist deformation when force is applied and directly relates to its firmness. If the consistency is off, it can lead to leakage and poor overall lubrication performance.


There are many aspects to consider when trying to select the best water-resistant grease for your machines. By understanding the different aspects of machines and what their lubrication needs are, you can properly identify which grease can help protect your machines, and protect you from costly failures and fixes.

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