Modern aluminum coolant systems are manufactured using Controlled
Atmosphere Brazing (CAB). Because of the way the aluminum parts are joined,
the outside of the radiator becomes passivated by the air––giving it a natural
protective coating––but the aluminum inside remains unprotected. And that’s a
big problem for heavy-duty engines that call for nitrited coolants.
Aluminum systems and nitrites don’t mix
When nitrited coolants hit unprotected
aluminum, an adverse reaction can occur,
causing increased coolant consumption, pH
imbalance, and in some cases, engine failure.