Originally posted by GS:
...Did extensive research and found that plastic is the only material that could be molded to produce an efficient design for water flow.
The metal impellar is a lot more shallow than the plastic, and some resources have stated that correct flow in the head is not achieved(prone to hot spots)....
Metal water pumps, as stated above by
DanB have been used for years in all makes.
I didn't notice any significant difference in metal impeller topography. I did notice nice sharp metal edges which should have no problems dealing with the bits of plastic now residing in my cooling systems. No change noted in operating temp; metal vs plastic, but that's why there's a thermostat.
