Water pump fin breakage. Causes?

Having overheating issues, just changed my water pump and 5 of the 6 fins were broken off...

What would be some possible causes of this?

 

Bearing so bad it was moving all over the place are there marks showing impacts

I hope that was not the original one.

That had to be quite loud when it happened .

 

No idea if it was the original. I've only had the truck 3 years. Don't know when it happened to be honest.

 

I wouldn't worry about HOW it happened.....

But WHERE is the broken piece????

 

Valid points. Fins could be lodged in the radiator or somewhere in the block. Not in the hoses as I've changed those and the thermostat etc... No idea how it happened either. I'm wondering if low fluid and cavitation could've done it.

I need to take some time and look at the original to see if there are impact marks on the side of the housing. If not cavitation/heating or just long term wear maybe did it?

Overheating in low fluid levels and then cooling repeatedly could make any metal fatigue I guess... where's our physics experts???

 

I had thought of freezing but then you would have a few more problems

 

You mean bearings freezing up? hard to say, it's not a high tension part, so can't tell... the belt didn't look melted.

 

Lack of proper Antifreeze temperature drops below freezing .

Most times it would cause lots more damage.

A bearing seizing depending on what engine you have would likely burn through the belt driving it with lots of smoke and squealing

You never heard strange noises before you pulled it apart

 

Its possible that the fins when stamped are to long and rubbing the block inside the water passage. Did you notice any scrape marks inside the block housing where the water pump is inserted into the block?

As an old aircraft sheet metal repairman there is something called bend radius that is there is a minimun allowance for the bend in sheet metal so if the fins were bent to sharp of a bend they can crack at the bend under pressure /stress (vibration ) and separate from the original piece .

Check your broken parts for cracks at the bend of the fins.
Just a suggestion

TOMB

 

no scrape marks, bearings weren't wobbly or noisy. Can't tell if there were any fresh shear marks where fins recently broke off, all very corroded. I'm guessing they rusted away to nothing in bad cooling fluid over a decade or more. Unfortunately that combined with a faulty temp sensor led to a very bad overheat. Gotta do a compression test now etc...

 

Poor cooling system maintenance if that was the case it might also be time for a new radiator

 

Did that while I was doing the water pump this week. Still getting some bubbling in the top hose, so now need to compression test the cooling system. Looks like I may be doing my first head gasket or head replacement if I'm not lucky.