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Helping Cooling Systems Keep Their Cool

Advances in cooling system technology and coolant chemistry have made it possible for engine manufacturers to greatly extend service intervals – and in some cases, eliminate the use of coolant filters. In fact, most Cummins MidRange engines have been operating successfully without coolant filters for the past decade, and that trend is now finding its way into Class 7 and Class 8 trucks, with the coolant filter now being optional on the 2015 ISX15 and ISX12 engines

But that doesn’t mean that your customers can just ignore cooling system maintenance altogether. This article outlines a couple of quick and easy maintenance and service tips that your customers need to follow to ensure long-term reliability and durability of their engine.

Hardware: While the cooling system hardware itself doesn’t require much in terms of maintenance other than checking hoses and seals, one important element is the radiator cap. Cummins engines come with a 15 PSI radiator cap, which helps to manage the boiling point of the coolant inside your engine. This is a higher pressure than that of prior years, so if you have to replace a cap, make sure it’s up to the task.

Fluids: The key chemical in antifreeze/coolant is either ethylene glycol or propylene glycol. The first offers better protection against freezing or boilovers, and is suitable for all climates, but it is toxic and must be handled (and disposed of) properly. Propylene glycol offers slightly better protection against issues such as liner pitting, solder bloom and corrosion, but will increase in viscosity at low temperatures, so it is not recommended for extreme cold weather applications. It is less toxic, but is still considered hazardous waste.

Types of Coolants: There are three basic types of coolants – conventional, organic and hybrid. Conventional coolants contain nitrites and molybdate with mostly inorganic additives, and are the lowest-cost option with the shortest service intervals. Organic Acid Technology (OAT) coolants offer the longest service intervals, and do not contain nitrites or molybdate. Hybrid coolants are a blend of the two. As seen below, different formulations of coolant each have a distinct color, helping to ensure that the correct matching coolant is being used for top-off.

fleetguard june 2015It is always a good idea when doing top-offs or complete flush-and-fill procedures for your customers to use the same type of coolant that the manufacturer or OEM used as factory fill. If there’s a question, your customers should refer to their Operations and Maintenance manual for guidance. Many late-model trucks that do not have coolant filters recommend that only OAT coolant be used.

Fluid Testing: The cooling systems on Cummins heavy duty and medium duty engines are designed for easy checkups and maintenance. Typically, when a vehicle is brought in for an oil change, it’s a good idea to double check the coolant fluid level (it can evaporate over time, even in a closed system) and top off, if necessary. Your customers should also check the acidity (pH), sulfates and chloride of the coolant, using a test strip such as the Cummins Quick-Chek™ CC2718. Then, if your customers are running conventional or hybrid coolants, they will need to check the strength of the nitrites and molybdates (OAT coolants don’t have these) using a test kit CC2602. These tests can be completed in two minutes, and provide accurate visual confirmation that the coolant has the right chemical composition to do its job.

The third and final test is a check of the freeze point, which can be performed with either test strips, a hydrometer or a refractometer. Cummins recommends the use of a refractometer because it is more accurate and eliminates potential issues due to variation in color perception.

If your customer’s cooling system does not pass the tests, a variety of actions will be indicated. If the coolant level is low, the customer will need to add more coolant. Cummins recommends a premixed solution to ensure demineralized water.

  • If the coolant package is inadequate (chlorides, sulfates or pH levels are off), a flush and fill should be performed.
  • If the additive level is low, use of a supplemental coolant additive (SCA) will be indicated, and the system should be retested to make sure adequate protection is provided.
  • If there is a clogged filter or other evidence of contamination in the system, then a complete draining, cleaning, flush and fill should be performed and the filter replaced.
  • Fleetguard® Compleat™ ES is the best choice for optimum performance, but customers can choose any coolant that meets the CES14603 standard.

Customers who choose to use a concentrate and add their own water should always perform a water-quality test, as hard water with excess amounts of calcium and magnesium salts can impede heat transfer and result in head cracking and oil degradation, while high chloride levels can cause corrosion issues. To be safe, customers should use demineralized or deionized water.

Some excellent videos have been produced by Cummins Filtration, and are now available for anyone to view on the Cummins Filtration YouTube channel. The videos provide additional information and recommendations for your customers to review.

Specific testing requirements and mileage/hourly recommendations for extended service intervals for cooling systems on Cummins engines are outlined in QuickServe® Online (QSOL) at Section 3 – Extended Service Intervals, Table 3, Fleetguard Recommended Coolants and Section 6 – Coolant Testing.

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