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Dent in Water Pump?

I was checking under my hood today and I happened to notice a dent in what I think is my water pump. Should this be cause for concern or something I can just ignore? Here’s the picture evidence:



Yes, this should be cause for concern. While it’s only the pulley, I’d be inclined to change the whole pump. I’d feel uncomfortable running a pump that had been subjected to that big a lateral impact.

Any idea how this happened?

My vote is for mountainbike’s advice. That’s a very unusual dent.

From the pic is that a fairly new belt? Could it be that someone was prying in there for some reason?

perhaps it was hit by a sparkplug that “shot out like a rocket”, they are known to pass clear through “headers”.

Belt is almost 4 years old at this point.

Thing is, that pump was only installed about 3 months ago. I can only assume (hope) that it wasn’t like that before they put it in. I also had a coolant leak about 3 days ago; it ended up being the heater core. I’m not really jumping at the chance to replace the water pump again.

Spark plugs are still firmly in place, thankfully.

Ignore the idiotic spark plug comment. Since the pump was replaced a few months back this could mean that someone pried the old pump off because it was stuck firmly to the engine. Odds are the new pump came without a pulley and this pulley was transferred over to the new pump, dent and all.

I would take the belt off, spin the pump by hand, and see if the bearing exhibits any roughness or play. If not, I would just replace the pulley and keep an eye on it. Worst case would be the bearing wears out prematurely, which would create a coolant leak you’d see, as long as you keep an eye on it and your coolant level. Best case, it lives a long and normal life.

Inside joke.

Did they pry the pulley off, or did they lock vise-grips on it to keep it from turning while removing the old bolts?
Note the matching scar on the front side of the pulley.


LOL…looks like someone forgot a wrench under the hood and it found its way into the pulley belt zone…you can swap that pulley no prob… as for pump integrity? You would already know you had an issue by now… Pump is prob fine…swap de pulley

Good advice to feel the pulleys motion…that will tell you if yo incurred any bearing damage…if it rotates smoothly with no play…you are good to go an swap the pulley My bet is the pump will be FINE

That sparkplug gets around. I hope it doesn’t find its way to the space shuttle.

My first inclination was that this was a very bad impact dent, but since the pump was just changed I’m inclined to agree with everyone that it was probably due to some ham-handed installation practices. I retract my initial comment about worrying about the pump and agree that turning the pulley by hand and checking it for lateral and axiial lpay should be sufficient to ensure integrity…or find out otherwise.

Replace the pulley, its damaged, and will only shorten the life of the serpentine belt, and the water pump if you keep using it.


I have not replaced a lot of water pumps on what looks to be a Cavalier in the late 90’s range, probably under 10. I have replaced quite a few alternators, what do they have in common? pulling up the tensioner (to release the belt) can be a problem if someone does not show you how (or you dont figure it out). Perhaps,just perhaps someone managed to use the pulley edge as a pivot point for a bar to release tension on the belt. When people get in a rush and they are confronted with a task that in their mind should not be giving them trouble, they resort to poor technique. The 3.1 Lumina of the same years can also be a little tricky to move the tensioner(the 3.4 Lumina is a bit of trouble also to get used to). I never have found the 3/8 square in the tensioner housing much help. I usualy fit a 15mm open end wrench around the tensioner casting and it just barely worked, but it worked.

The mechanic was stressed… At least it’s cheap to fix.

Another look and I think you’re right about the vise-grips or Channel Locks.
Note there is still some bare metal there that has not rusted completely over so it was done not too long ago.

It sure makes you wonder about the pulley transfer. Someone blind enough not to notice that damage or they noticed and thought they would get away with one maybe.

I’m sure this is exactly what happened. It is a 1992 Cavalier and it was the original water pump being replaced, I can see how that could become firmly stuck to the engine. I’ll get the pulley replaced and have them check the integrity of the pump. Thanks for your help.