Coolant Management: It’s More Important Than You Think

Coolant management may not always get the same attention as other preventive maintenance tasks on a mine site. In some cases, operators can view coolant management as an opportunity to reduce costs – seeking short-term savings through more simplified inventories and maintenance routines.

But in the long run, these quick savings can come at a significant cost. In high-horsepower mining engines operating under heavy loads and demanding duty cycles, proper coolant management is vital to preserving engine integrity, maximising equipment availability and preventing costly failures.

The real cost

Improper coolant use in heavy-duty engines can even lead to serious risks like cavitation – ultimately causing cylinder liner damage and even complete engine failure. In any size mining operation, this leads to costly downtime and repair expenses, but especially in large fleets, millions of dollars are at risk. So, let’s talk about coolant management: what it means, what’s at stake and what can be done.

Coolant 101

When it comes to our everyday cars at home, we think of engine coolant as a necessity – to remove heat from the engine and prevent overheating. While temperature regulation is certainly one of its primary functions, a modern coolant used in high-horsepower mining engines is far more sophisticated than simple mixtures of water and antifreeze.

Today’s engine coolants contain carefully balanced combinations of water, glycol and specialised additives. These formulations are designed not only to manage temperature, but also to protect engine components from corrosion, cavitation, scale formation and chemical degradation.

Let’s break down the primary functions of engine coolant to further understand why coolant management is so critical for today’s advanced mining engines.

• Temperature control
  Choosing the wrong coolant – or managing the coolant levels incorrectly – can compromise the cooling system’s ability to regulate the engine’s temperature, increasing the risk of overheating and reduced performance.

• Freeze protection
  The right formulations and coolant maintenance will prevent freezing and expansion of cooling system fluids, which could crack engine components and cause extensive damage.

• Liner pitting protection
  Vibrations over time can create rapid pressure fluctuations in the coolant, allowing small vapour bubbles to form. This gradually erodes the liner surface, creating pits that deepen and become perforated – allowing coolant to leak directly into the combustion chamber.

• Corrosion protection
  The right engine coolants contain corrosion inhibitors that form protective barriers on metal surfaces, helping extend component life and maintain engine reliability.

• pH buffering
  By using the latest coolants and keeping up with a regular maintenance schedule, operators can maintain stable pH levels – preserving coolant performance and protecting system components from chemical damage.

• Scale and deposit prevention
  With the right formulation, today’s coolants help prevent excess mineral deposits from forming – ensuring efficient heat transfer and reducing the risk of localised overheating or hot spots within the engine.
• Foaming and aeration control
  Entrained air can reduce coolant pressure and collect in certain areas of the engine, reducing cooling performance and increasing the risk of localised overheating and cavitation. Proper coolant formulation preserves the anti-foaming properties of the coolant for the entire life of the coolant.

Different engines? Different coolants.

Not all mining engines are created equal – and not every coolant is formulated for every engine.

That’s why manufacturers develop coolant specifications tailored to the unique characteristics of their engine designs. Differences in materials, liner configurations, cooling jacket geometry, coolant flow paths, operating temperatures and coolant flow characteristics all influence coolant requirements.

Manufacturers also apply different approaches for managing cavitation. Some designs rely more heavily on chemical protection through coolant additives, while others incorporate mechanical design features to reduce cavitation risk.

As engine technology evolves, manufacturers often update coolant specifications to address new performance requirements. Some operators may be using earlier specs for Dissolved Coolant Additives (DCA) or Organic Acid Technology (OAT) coolants, but modern high-horsepower engines like Cummins provide require different coolant chemistries than their predecessors – making it essential to follow current manufacturer recommendations.

The move toward lower-toxicity coolant components, such as propylene glycol or glycerin, can also significantly change coolant properties and performance. That makes it important to consider the full coolant formulation to ensure it delivers the protection and performance the engine requires.

The consequences of using the wrong coolant

Using the wrong coolant can have a ripple effect across the entire fleet. When the coolant chemistry doesn’t line up with engine requirements, it can jeopardise engine reliability in a multitude of ways, with liner cavitation being a common outcome and amongst the most disruptive.

What exactly does this look like inside the engine? As the piston moves, it causes the cylinder liner to vibrate. That vibration creates rapid pressure changes in the coolant around the outside of the liner. In areas of lower coolant pressure, tiny vapour bubbles form, and when pressure increases again, those bubbles collapse instantaneously. That collapse creates microscopic shock forces that remove material from the surface of the liner. Over thousands of hours, this repeated effect can lead to pitting and eventually perforation of the liner, allowing coolant to leak into the cylinder. If enough coolant enters, it can cause hydraulic locking or contaminate the lubricating oil system, causing further damage elsewhere in the engine.

If liner cavitation is caught early, liners can be replaced during mid-life maintenance. However, if this goes unchecked and major damage occurs, operators are left with a significant rebuild and associated costs and downtime.

How to manage your fleet’s coolant properly

Effective coolant management begins with selecting the correct coolant for the engine application. Operators using Cummins high-horsepower engines should follow the “Fluids for Cummins Engines” Service Bulletin for more details, available through authorised Cummins service providers or in digital format via quickserve.cummins.com.

Routine cooling system maintenance is equally important. Leaks should be addressed promptly through both daily inspections and scheduled maintenance programs to prevent contamination and coolant loss.

And when it comes to “topping up” – be sure to refill with coolant and not just water. It may seem harmless, but repeated additions of water gradually dilute the coolant’s additive package, which reduces its ability to provide corrosion protection, cavitation resistance, freeze protection and pH control.

Looking ahead

Simply put, engine coolant is the lifeblood of every engine in your fleet. It’s not just there to manage temperature or prevent overheating. Quite literally, it helps keep critical engine components in good operating condition from the first turn of the key to the last.

As the mining industry moves toward hybrids and electric-powered equipment, coolant management will become more important than ever, extending beyond engines to include batteries and electronic systems as well. Mining operators around the world will focus more each year on investing in the long-term health of their fleets – and, in many ways, it all starts here, drop by drop.