Some antifreeze, although labeled as safe for aluminum parts, may not be compatible with Acura cooling system components. Extensive research and testing by both Honda R&D and CCI, the manufacturer of the Honda coolant, have proven that the abrasive silicates and/or borates found in most domestic coolants can cause these problems:
- Silicates bond to the surface of the water pump seal and act as an abrasive, causing considerable seal erosion and coolant leakage. In actual tests, the silicated coolant caused early leakage. This leakage increased dramatically until a substantial portion of the coolant had been lost. In contrast, the Honda coolant had almost no leakage through the duration of the test.
- Silicates tend to gel and settle in the coolest parts of the cooling system, causing radiator plugging and overheating.
- Borates cause pitting corrosion on the cylinder head.
- Silicate inhibitors are difficult to stabilize and, therefore, limit coolant shelf life.
Most commercially available coolants were originally designed for cast iron engines. Silicate, an inexpensive additive, was added to coolants to prevent aluminum corrosion, but the long-term durability of the combination was not tested.
In contrast, Honda coolant was designed specifically for aluminum engines. It contains an organic corrosion inhibitor instead of silicate. This superior formula gives these advantages:
- No silicate abrasion of water pump seals. For example, these graphs show the surface roughness of two aluminum water pump seal rings. Seal A, exposed to silicated coolant, shows considerable damage. Seal B, exposed to Honda coolant, displays only minute wear.
- No plugging or overheating caused by silicate gelling.
- Excellent corrosion protection for aluminum components.
- Long-term corrosion protection for other cooling system materials (steel, cast iron, copper, solder, gaskets, seals, and O-rings).
