LO 11-5 Describe and explain the classification, composition, and applications of various antifreeze formulations
1. Antifreeze Formulations
1.5. Maintaining Types II and III Fully Formulated Antifreeze
LO 11-05: Describe and explain the classification, composition, and applications of various antifreeze formulations. |
Maintaining Types II and III Fully Formulated Antifreeze
When antifreeze is retailed as fully formulated, it contains a pre-charge of any required SCA/DCA additive package. To maintain these fully formulated antifreezes at every preventive maintenance service—or at least twice per year—the color and freeze point of the coolant are checked. If the coolant is the correct color, has no deposits, and has a freeze point between −15° F (−26° C) and −60° F (−51° C), then the coolant is considered to be in suitable condition for further use.
Mixing IAT with OAT, HOAT, and NOAT antifreezes will not damage the engine’s cooling system. However, mixing antifreezes nullifies the extended-life attributes of these formulations. Depending on the type of formulation, acceptable contamination can range from 5–25%, though most OEMs do not recommend allowing contamination to exceed 5%.
It is easy to be confused with the variety and complexity of antifreeze formulations available for use. Therefore, it is imperative that the technician and diesel engine owner be fully aware of and carefully follow the vehicle manufacturer’s requirements and recommendations for antifreeze.
| Technicians Tip | ||
| If the coolant is brown in color, it often indicates the presence of rust. Some corrosion inhibitors used to prevent rust are easily damaged by overheating coolant. Coolant that has overheated should not be reused during service. |
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