Actually, there are pros and cons for each type of impeller. The metal ones are usually pressed pot metal. They could react more than the nylon ones if you allow your coolant chemistry to go sour and wear more. The nylon ones are maybe lighter and so draw slightly less HP. The differences are probably so minimal that it really doesn't matter.
Besides, this is not what failed (nor does it usually). The bearing is the likely culprit and either caused the pump/pulley to sieze, or as ToolPants described, it started wobbling, taking out the shaft seal with it (which is where the leak is coming from).
I've replaced maybe a dozen waterpumps in my time and always used a rebuilt one with no issues whatever. In fact, in a couple cases, the rebuilds lasted longer than OEM. Plus, they are almost always significantly cheaper.
Be sure to inspect the old pump when you remove it to account for all the mass. You wouldn't want to have pieces of the old seal or impeller flowing through your cooling system where they could cause blockage. If you find debris, or that impeller is very worn, you might think about flushing the system as part of the repair.
|