Mechanical Water Pump Lifespan?

Water pump for engine is rarely an issue in Prius... Like the rest of the car, you're barely 1/3rd of the way into its likely lifespan.

 

prius were not designed to save money, but the world. in for a dime, in for a dollar, now that you've done the brake actuator, sell the cat and put in a 'newpriusbatteries'

 

are they over tightening the belt?

see my edit

 

i would call it very unusual. i wonder if there is an underlying cause

 

If a third one needs to be put in that's when it will be essential to find the underlying cause.

 

Wow, that is unusual and that's a heap of money to have to throw into her. FWIW, if it were me, if the car had any more high-dollar expenses I'd be looking at replacing her with something more reliable...even Toyota's can reach a "not worth it" phase!!

 

Belt tension was going to be my guess. The water pump on my 2001 was still original when I parted with the car at something like 238,xxx miles. I do not hear of them failing in 40 to 50k unless something is making that happen. Excessive belt tension puts a high side load on the pump bearing and is one known way of making that happen.

If it isn't that, I wonder if it could be something like the engine mount / idler pulley thing being misaligned, or the crankshaft or water pump pulley being out of round or something (I assume the pump comes without pulley, and the pulley is swapped over?).

One way or another, something isn't right.

 

I say the mechanical water pumps don't fail. My first 2005 Prius went 287,000 miles and no battery or water pump issues. Got rear-ended by a panel truck then a tree fell on the front. Insurance bought the car. Got a used 2005 in an estate sale 197,000 miles with a bad battery, red triangle. Put a new hybrid battery in guaranteed for life and now have 314,000 miles. No water pump issues. The only issue I see currently is a noise I think is coming from the idler pulley (stethoscope has more noise from idler than water pump and there is no leakage from pump) I need to pull idler and inspect to confirm it is bad. If not, then the water pump. Only maintenance so far is tires, wiper blades, oil, filter, struts, shocks. Much less than 6 cents per mile to operate. But current noise has me concerned. It started about two weeks ago. I should add, daughter spun out and into snowbank last winter. Car now has a new front bumper lower panel but all under covers are missing. I'm hoping the noise is being caused by dirt thrown up from underneath but stethoscope says that's unlikely. I haven't been able to find a history of idler pulleys going bad.

 

So what do you say to someone who has two of them fail in the car's first 94,000 miles?

 

I am on my 4th engine water pump at 160k. The only part I replaced more times are the tires, already on the 5th set.

I installed the second water pump at 40k replacing the original. I probably over tighten the belt so it lasted just 10k mile. I had ordered a CARDONE one online from rockauto.com for like $45 with lifetime warranty.

In 2010, I installed the 3rd water pump at 50k miles. I did not pay again for the part since it was under warranty but I spend another two hours of personal labor.

This year at 155k miles and after 105k miles/11 years later the water pump started leaking from the weep hole. I found the email from my old order at rockauto.com and ordered a free replacement. I installed it and I hope the 4th water pump will last another 10 years.

The total cost for all water pumps is $45 since the rest are warranty replacements but I am tired of doing the same thing over and over. I have done both the under the car and over the car methods and it is much easier to replace it from the top.

 

What are you using to set the belt tension?

 

I do not have a tool to measure force on the belt. If I remember correct I tried to press about 20 lbs of force to get the belt moving about 0.5” in the center of the longest run. No exact tension.

An easy check is to twist the belt at the same point. The correct tension is when it is just turns 90 degrees. If turning less is too tight and will destroy the water pump. Too lose will turn close to 180 degrees.