[Jake Raby]

The pump can fail in at least 3 ways, two of which aren't catastrophic for the pump.

1- Bearing failure: this is audible and generally is noted before the engine is driven further

2-Complete impeller failure: this can lead to a compromised engine, but usually makes enough noise and the temps climb high enough that the car is shut down and towed home safely. In this scenario the cooling system is filled with foreign object debris that can block a capillary in a cylinder head and lead to a crack.

3-Partial Impeller failure: This is the scariest of all because there are no sounds, no noises and nothing out of the ordinary. In this type of failure a small chip off an impeller blade detaches and ends up floating around in the coolant until it finds a capillary to block. When this happens the engine gains a cracked head and then gets intermix out of the blue.

Then people start misdiagnosing the issue as a heat exchanger, bad head gasket, etc and they will sometimes repair the cracked head and never even pull the damn water pump which caused the issue to begin with!!

If not caught in time the intermix contaminates the oil and kills the cylinders, then the engine is dead, like the 4 I have downstairs right now that are all here and all dead because of the damn waterpump.

What you guys need to remember is that a component doesn't have to grenade to create collateral damage that will kill the engine.

If an engine has lost an impeller, or has a chipped impeller that broken piece must be found, even if that means complete disassembly of the cooling system. If you can't find it, its probably already jammed inside a cylinder head~

We learned this while repairing heads and milling the cracks open... When finding pieces of impeller blades inside the cylinder head cooling passages one can feel pretty confident as to what the issue is and why its occurring.. We had 13 of those instances in 2010.