Coolant is just as important as oil when it comes to protecting your engine.
Since roughly 40 percent of engine problems occur because of coolant-related issues, it’s easy to see why engine coolant is almost as important as oil for protecting your engine. Most people know that coolant’s main job is to protect the engine during extreme temperatures, keeping it from overheating or freezing, but coolant also plays an important role in protecting engine parts from corrosion, pitting, cavitation, scaling, deposits and acidification. For example, tiny air bubbles traveling at high velocity can damage the water pump over time, but a supplemental coolant additive (SCA) acts as a chemical barrier, protecting the pump from damage. Likewise, for cylinder liners, radiator tubes and more.
Four Types of Engine Coolants
Engine coolants fall into one of four main types and range from lower-cost versions that need more frequent service to extended life versions with much longer maintenance intervals. Always be sure to check your engine manufacturer’s specifications first to see what type is recommended for your engine. Backed by 50 years of experience in coolant chemistry, Cummins Filtration Fleetguard has a full line of coolants to fit the needs of hard-working diesel, natural gas and gasoline engines. (https://www.cumminsfiltration.com/sites/default/files/LT36351.pdf.) Made up of distilled water and other clear chemical formulas, coolants are typically dyed reds, yellows and blues (and sometimes purple or pink) so that you can easily identify the coolant and spot a leak.
Here’s a quick break-down of the main coolant types:
- Inorganic Acid Technology (IAT): The original, lower-cost, often green or pink, liquid that comes to mind when you think of coolant or antifreeze, IAT coolants are conventional, low-silicate formulations and typically used in cars and light-duty trucks. For heavy duty engines, IAT coolant varieties come pre-charged with SCAs that protect the engine from pitting and corrosion. IAT coolants need more frequent service and recharging with SCAs about every 40,000 kilometers. (Always check the manufacturer specs for your engine.)
- Organic Acid Technology (OAT): Organic acid formulations make up this type of coolant, which has extended service life for longer service intervals. These coolants last much longer than IAT varieties and are for use in all heavy- and light-duty diesel engines, as well as natural gas and gasoline engines. If properly maintained, some OAT coolants can provide around 1,600,000 km or 20,000 engine hours of service.
- Nitrited Organic Acid Technology (NOAT): Similar in makeup to OAT, NOAT coolants employ nitrite and sometimes molybdate for engine liner pitting protection. NOAT coolants also offer extended service life and can be used in heavy duty ELC, NOAT and EC1 systems. (Check the manufacturer’s specifications to verify.)
- Hybrid Organic Acid Technology (HOAT): This combines some of the inhibitors used in IAT and OAT coolants, and is usually a low-silicate, nitrite/molybdate-based technology. HOAT coolants may need SCAs added at the service interval, typically around 241,000 kilometers or at the manufacturer-specified interval.
Because the chemical additives in coolant can break down over time, you’ll want to test it regularly and either top it off, change the filter, or recharge the SCAs. Three-way test strips are a quick, easy way to measure freeze point, molybdates and nitrites in IAT, NOAT, and HOAT coolants so you know about a potential problem before it manifests. For OAT coolants, you’ll want to use the four-way test strips, but it’s important to note that OAT test strips are often specific to one product and can vary in test parameters. Cummins Filtration’s 4-Way Test Strips will check the freeze point, pH, and molybdate concentration of the coolant, while also providing a nitrite-contamination test pad. Test strips come with a color chart to help you decipher the readings and determine if you need to replace the coolant filter or add additives. Recommended test intervals are as follows:
- IAT: Every oil drain or at one year
- HOAT: Every 241,000 kilometers, 4,000 hours or one year (whichever comes first)
- OAT: Every 482,000 kilometers, 6,000 engine hours, or one year (whichever comes first)
When adding top-up coolant, it’s important to make sure you’re adding the right type. It’s best to avoid mixing when possible, and if you do mix, the same formulation type should be added. For example, HOAT coolants should not be mixed with OAT or NOAT solutions, and vice versa. Also make sure you’re adding at the right dilution. Coolants are sold in a variety of dilutions, from concentrates to pre-diluted mixtures. If you’ve bought a used engine and want to convert it to a different coolant system, it’s best to perform a complete system drain and flush unless following a specific conversion program from the coolant manufacturer. While draining and replacing the coolant may seem expensive at the outset, it’ll be more cost-effective over time to switch from an IAT or HOAT coolant to an extended life coolant that requires less overall maintenance and labor. Again, it’s important to always check your engine manufacturer’s specifications to select the right type of coolant. Cummins has a detailed cross-reference guide for choosing the right Fleetguard coolant.
To learn more, check out Cummins Filtration Fleetguard full line of coolants, cleaners and test strips, designed for a wide range of heavy-duty diesel, natural gas and gasoline engines.
Have further questions answered by watching the videos linked below.