What else should be replaced when replacing the water pump?

My impression is that coolant pump failures at such low mileage are rare, assuming it hasn't been coping with overheated coolant.

When the pumps have to be replaced, people often replace the coolant thermostat at the same time, because it's easy then. However, I've yet to hear of an original thermostat actually failing at any mileage.

 

I still don't understand why Gen3 owners have been so passive about engine destroying ability of this valve failure via class action lawsuits? Head gasket failure due to a stuck valve boosting engine temperature is a smoking gun... Guess its not common enough for outrage of significance?

 

Which valve? Maybe pre-edit?



^ got this alert too, Priuschat snafu?

 

I got confused when reading this first time around and thought OP was mentioning a different valve, rather than just the EGR valve itself. Once I realized it, I edited you and Chapman out of me asking for help, but notification was already sent.

Point being this is the first thread I've seen that specifically said valve was jammed and forcing engine temperature higher. As in cause and effect, which is much less vague than how others have presented EGR issues in the past.

 

Looks like maybe you mixed up this thread with the other recent one where the exhaust heat recirculation system was being discussed. That system has the little wax-thermostat actuator down on the exhaust pipe that waggles an exhaust valve, controlling whether the exhaust goes straight through the pipe, or has to go through the EHRS heat exchanger and heat up the coolant. If the valve gets stuck in the latter position, it heats up the coolant more than intended.

In that other thread, rjparker posted graphs of the two temperature sensor readings, one at the engine water outlet, and one at the coolant return from the EHRS exchanger. The graphs show that your signal of the sticking valve is likely to be a temperature-warning light because of the EHRS temperature reading, while the engine temperature reading stays relatively tame. So you get notification of the EHRS issue and, ideally, go unstick it. I'm not sure how much excitement should be attached.

 

Perfect example of the LLM problem solved via a select all for reply... As in it lacks critical oversight / quality control. For example, there's no Serpentine belt in a Gen3 Prius. There's also only one or two things on that list that are relevant... Or as my personal AI was explaining to me earlier this evening:

"AI reaches for rhetorical scaffolding the way a nervous speaker reaches for filler words. Brevity is harder because it requires knowing what to omit, which requires genuine judgment about what the reader already knows and what actually needs saying. AI tends to over-explain because it can't fully model that gap." --Claude

 

Actually it addresses none of the most common failure paths.

Head gasket failure - design flaw
Excessive Oil Burning - design flaw
Inverter failure - design flaw
Brake Booster Assembly -design flaw
Hybrid battery - expected around 150k or higher

Each was repaired free if they failed within certain timeframes and mileages.

Improved parts include head gasket, pistons, rings, inverter power electronics and perhaps brake booster since repeat problems on the last item is rare.

Sure you should do regular maintenance on fluids and spark plugs. Generally fluids twice as frequently as the maintenance schedule recommends. Plugs are ok as recommended around 100k. I believe oil and coolant are key. If its not burning any observable oil in 5k miles you want to keep it that way. Change the brake fluid every 50k.

I have never changed my water pump in 350k miles. But I do have a temperature display with an early audible alarm.

P10 display $35


Change the fluids. Save for a new hybrid battery.