Cavitation Corrosion of Aluminum Water Pumps

Aluminum water pumps are susceptible to physical erosion attack. The pump to the right was damaged in a severe laboratory test in only 5 days' time. The laboratory test, ASTM D2809, predicts the ability of a coolant technology to prevent premature water pump failures. This kind of failure will obviously result in poor pump efficiency and engine overheating.

To prevent this type of damage, coolants complying with ASTM D3306 and ASTM D6210 are tested and must protect the pump well enough so that only superficial (less than 0.4mm deep) damage occurs.

Proper use of coolant additives often provides extra protection, but excessive use of additives has been associated with premature seal failures.

Soluble oil products are not recommended. These were used decades ago and some are still marketed. They are not effective on today's engines, and this laboratory has seen instances where they have attacked modern hose materials resulting in failures.