Everything You Need to Know About Subaru EJ Water Pumps

We receive a ton of questions about what makes certain parts different or better than others, so we're going to break down some of the things that make certain parts unique, and we're getting started today with water pumps.

There are some different options from Aisin, Company23,  Subaru OEM, and RCM with different features to fit your needs. The biggest difference among these pumps is the impeller wheel itself. 

The factory pump and other OEM-adjacent pumps typically use an impeller wheel that is shaped from stamped steel. The thin metal blades can potentially cause cavitation, which in turn weakens the the wheel and reduces the longevity of the pump.

On the other hand, an improved pump like the RCM Black Series features a cast impeller wheel. Using a cast wheel naturally improves the strength and longevity of the pump, but it also allows for an improved design to reduce the chance of cavitation and improve flow. 

If the Black Series seems like a bit much for your build, RCM does offer a factory pump with their cast impeller wheel inside. All of these are available now at the links below!