I was under the impression that the Aisin water pump was the oem for EJ22, but I have also heard paraut was used by Subaru.I found these two on Amazon, and I was wondering which one I Should buy? There also a big price difference, and I'm not really sure why.
I just did a Waterpump and Timing Belt on my EJ22 Legacy and the pump that was ON the car was a Parut. I had purchased the AISIN as a replacemet based on recommendations I found on here and the fact it was made in Japan. When I pulled the Parut I noticed that the impeller on the pump was completely different than the Aisin. The Aisin impeller was a stamped piece while the Parut was a cast piece of completely different design (what you see in the picture), but the Aisin shipped with a completely different design. That's not to say the Aisin is any better or worse, but it's obvious that the newest design is a cheaper one. My confidence was also broken when my co-worker's Toyota 4runner suffered catastrophic bearing failure in his water pump which was an Aisin branded unit from Napa after just under 40K miles.
This is what's on the Aisin now
compared to the old: