In many ways, coolant is the lifeblood of an engine. Coolants and antifreeze transfer heat away from the engine, protect metal, inhibit corrosion and protect engines from freezing in extreme temperatures.

But the wide variety of coolants, and different specs for their use, can lead to confusion for many owner-operators and fleet managers. In fact, an estimated 40 percent of heavy-duty engine problems can be traced to poor coolant system maintenance.

Manufacturers have tried to eliminate confusion by adding colored dyes to coolants. The dyes differentiate the different types of coolant, and distinguish them from water and other underhood fluids.

Some of the most common heavy-duty truck coolant colors are:

Although NOAT and OAT coolants work in similar ways, nitrite-free OAT coolants are preferred for modern engines. That’s because modern engines have more aluminum components, such as brazed aluminum heat exchangers, and nitrite-free coolants offer better protection for aluminum. Neither OAT nor NOAT coolants require SCAs.


Because coolant types also differ in their lifespans, Road Choice offers four popular categories to meet every application and service interval:


Both Road Choice Extended Life NOAT and Nitrite Free Extended Life OAT are compatible with green and pink coolants, and can be used to top them off. However, switching to an extended life coolant, or ELC, is often a better and more cost-effective choice. Although ELCs cost more than conventional green coolants, they do a better job of protecting engine components, provide better heat transfer and corrosion protection, eliminate the need for SCAs, and require less downtime with their longer maintenance intervals.

Road Choice coolants are available in both concentrated formulas and pre-mixed 50/50 blends. And like all other Road Choice products, they’re backed by a minimum one-year warranty.