Coolant is important in your equipment’s cooling systems to prevent freezing, overheating, corrosion, cavitation and rust. A periodic coolant analysis can provide important information about the health of your machine.

What’s in coolant?

Nearly all heavy-duty antifreeze is about 95% ethylene glycol and 5% water and additives. About 1% of all antifreeze sold is made from propylene glycol, an alternative to ethylene glycol which is less toxic, but more expensive. By mixing glycol with various ratios of water, coolant is created. Typically, coolant should be a 50/50 glycol/water mix.

Formulations differ with the additive package that’s blended into the ethylene glycol. All of these additives fight rust, scale and corrosion but may have different chemical compositions. In diesel engines the additives also protect wet cylinder sleeves from cavitation.

What to look for when buying coolant

  • Pick an antifreeze type suggested for that specific make and model of machine based on equipment manufacturer recommendations.

Maintenance Recommendations

  • Periodic visual test
    • Visibly check fluid and color—should be clear of any contaminants or particles, indicating no rust is present, and showing that it has not mixed with another type of antifreeze.
  • Test additive concentrations with a coolant analysis test by taking a sample and submitting it for analysis. The recommended interval for testing is 1,000 hours.
  • Sample strips are available to test additive concentrations yourself. Using paper chemically sensitive test strips, you can see problems from color changes which indicate freeze/boil point (glycol content) nitrite (or nitrite/molybdate) levels and, in some instances, pH.

Conventional Coolants & OAT Coolants for Case Machines?

  • Conventional Coolant
    • Relies on inorganic inhibitors such as silicates, nitrites, and phosphates for corrosion and cavitation protection.
  • Organic Acid Technology (OAT) Coolant
    • Relies on inhibitors such as organic acid salts for corrosion and cavitation protection.
    • Actifull OT coolant or OAT coolant meeting MAT 3624 specifications is mandatory for all FPT Tier 4B final engines.  Never mix OAT coolant with conventional coolant.  Under no circumstances should you top off a cooling system with only water.  You can use a refractometer to check the concentration level.  Supplemental Coolant Additives (SCA) should not be used when using Actifull OT coolant.  Change the coolant solution at the change interval recommended.