Replacing water pump rotor vs entire unit

If you already ordered one, just install it and give it a go. I put one on my car with 215k miles and it still working nicely. It may not last the 150k miles that an original part can last, but you can replace it next time you drain/refill your coolant again.

 

I just replaced the rotor in mine about 100,000 miles ago... no issues...

 

I cleaned the whole EGR circuit at 120K and contemplated changing out the water pump at the time with one of those Amazon Aisen units with the Toyota ground off the housing. It would have been a good time to do it since I drained the original coolant out to do the EGR cleaning.

I read that those pumps tended to fail early, so I ended up leaving the original pump in the car.

I have subsequently bought a replacement rotor, so I have to to decide whether to change the rotor only in the original pump, or install the replacement pump (Toyota ground off) with the replacement rotor installed in it. Decisions, decisions.

Currently, the car is at 135K.

SM-G781V ?

 

That may be the way to go. I googled:

replacement rotor for Aisin WPT-090

And got lots of results, including this on Amazon.ca, for $37 CDN.

Any trick to getting the rotor out, maybe some sort of circlip?

 

Replacing just the rotor is easy. There is a tiny "o" ring holding it in place.
Check the original one for cracking white plastic, or fan blades.
I was going to leave the OEM on in place, until the pump slipped out of my hand and
I broke the empeller...... So I put the new one in....

 

I just replaced rotor too. It the only part of the water pump worn out.

Here is my old 120k miles rotor from Prius 2010.

Some people will get cracked plastic parts.

 

A small part that ultimately affects the entire engine.
If it is damaged, the temperature in the cooling system increases, overheating, breakdown of the engine head gasket, seizure, engine cemetery.