Water pump longevity ????

[WorkInProgressK]

Originally Posted by CN58

Have a 99 Boxster w/ 91K.. Runs perfect.. Read about water pump and stat failure.. So I decided to change them.

Changed the water pump and stat this w/e. The old pump looked perfect, no shaft movement. The composite impeller all intact. How long does a water pump last in these cars ?? I've heard some horror stories about pumps failing and spitting pieces of impeller into the system.

Went with metal impeller pump and a 71C stat. The other question is ?? Will the 71C stat help bring the temp down a few degrees. Ran a 'little" warmer than I liked last summer.. Anybody got experience with the swap to a 71C stat ??

Water pumps usually needs to be changed when timing belts get changed. Since our cars are chain driven it's a stand alone process at around 60000miles or 100000km. Water pumps tend to fail un-dramatically usually. They leak coolant thru a hole once the bearings gain some play. Considering the location of the engine, it would be hard to pick up. Now the plastic pumps might fail earlier, but that would be due to lack of coolant maintenance and just poor design of the composite.
Source:
"https://www.renntech.org/forums/topic/29955-need-help-identifying-coolant-leak-source-under-986/"

About the 71C thermostat. What tells you that you need to bring down the temperature? A proper working system is all you need. Someone might have tested the full opening temperature of a 80C vs 70C, at WOT (Wide open trottle) your car will be running at around 90-100C and flow will be the only thing limiting your cooling. The only thing you will be doing with the 71C is that on cold days, your oil will be 10C lower then normal because of the oil to water cooler. Which is bad since oil should be running at 100C+ to allow the removal of all water condensation in the engine.

Source: "https://www.bobistheoilguy.com/forums/ubbthreads.php?ubb=showflat&Number=632716"

Good luck!

[Cbonilla]

One point. I've repeatedly had it drilled into my head, by smarter people than I, is to avoid water pumps with metal impellers like the plague. When that pump fails (when, not if), the wobbling metal impeller will be chewing up part of your block. That will result in an increased gap between the impeller and block, leading to poor water flow. And it can't be fixed short of a new block. I'd much rather sacrifice an impeller than an engine block.