A higher degree of knowledge about engine coolants

Frequently Asked Questions

What are you looking to learn? Choose one of our commonly asked questions to find a Coolant U module that fits your needs.


Coolant is a transportation fluid that helps maintain optimal engine temperature under different conditions, among many other important features. Learn more about what coolant is in Module One.

Coolant is primarily comprised of water, glycol, and corrosion inhibitor packages. Learn more about coolant composition in Module Two.

Corrosion inhibitors protect internal engine components against the harmful effects of corrosion, cavitation, and erosion. Learn more about corrosion inhibitors in Module Three.

Global coolant products vary dramatically in terms of protection offered and composition, based on regional regulations. Learn more about global coolant manufacturing in Module Four.

LD coolants are suitable for light-duty (primarily passenger) vehicles, while HD coolant can be used in large-scale commercial vehicles and machinery. Learn more about the differences between light and heavy-duty coolant in Module Five.

IAT, OAT, and hybrid coolants are distinguished by whether their corrosion inhibitors are based on inorganic technology, organic technology, or a hybrid of both. Learn more about LD coolant best practices in Module Six.

The four main categories of LD coolant are Universal, Extended Life, Global Extended Life, and OEM badge specific. Learn more about their different compositions and capabilities in Module Seven.

HD coolant without the proper anti-foaming agents can form small air bubbles inside of an engine system, which then burst, resulting in cavitation. Learn more about HD coolant formulation in Module Eight.

OAT coolants do not need supplemental coolant additives to stay effective; increasing uptime and generating savings in the long-term. Learn more about HD coolant best practices in Module Nine.

HD Expert’s product line-up includes Classic, Premium, Extreme, Endurance, and Extra. Learn which HD Expert coolant solution is ideal for you in Module Ten.